<?xml version="1.0" encoding="UTF-8"?>

<!--XBRL Document Created with the Workiva Platform-->
<!--Copyright 2026 Workiva-->
<!--r:019e41f4-7c83-7296-b45c-f100fedd373b,g:708a6400-52ca-4029-80d7-6ef202f87d8f-->
<link:linkbase xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd">
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/all" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#all"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#hypercube-dimension"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-default"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-domain"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/domain-member" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#domain-member"/>
  <link:roleRef roleURI="http://www.firstmerchants.com/role/CoverPage" xlink:type="simple" xlink:href="frme-20260630.xsd#CoverPage"/>
  <link:definitionLink xlink:role="http://www.firstmerchants.com/role/CoverPage" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityInformationLineItems_019e41f4-826b-7e97-91dc-07f7704191db" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityInformationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntitiesTable_019e41f4-826b-7472-bd31-383b27fab240" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntitiesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_dei_EntityInformationLineItems_019e41f4-826b-7e97-91dc-07f7704191db" xlink:to="loc_dei_EntitiesTable_019e41f4-826b-7472-bd31-383b27fab240" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementClassOfStockAxis_019e41f4-826b-722c-8904-7dfe284dee3b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementClassOfStockAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_dei_EntitiesTable_019e41f4-826b-7472-bd31-383b27fab240" xlink:to="loc_us-gaap_StatementClassOfStockAxis_019e41f4-826b-722c-8904-7dfe284dee3b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_019e41f4-826b-722c-8904-7dfe284dee3b_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_019e41f4-826b-722c-8904-7dfe284dee3b" xlink:to="loc_us-gaap_ClassOfStockDomain_019e41f4-826b-722c-8904-7dfe284dee3b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_019e41f4-826b-7804-8d8b-7d1fe202c4ba" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_019e41f4-826b-722c-8904-7dfe284dee3b" xlink:to="loc_us-gaap_ClassOfStockDomain_019e41f4-826b-7804-8d8b-7d1fe202c4ba" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockMember_019e41f4-826b-7199-83cf-d4f2af4ac255" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_019e41f4-826b-7804-8d8b-7d1fe202c4ba" xlink:to="loc_us-gaap_CommonStockMember_019e41f4-826b-7199-83cf-d4f2af4ac255" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_DepositarySharesMember_019e41f4-826b-750b-8dc8-2aff53f39a2a" xlink:href="frme-20260630.xsd#frme_DepositarySharesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_019e41f4-826b-7804-8d8b-7d1fe202c4ba" xlink:to="loc_frme_DepositarySharesMember_019e41f4-826b-750b-8dc8-2aff53f39a2a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentType_019e41f4-826b-7a51-8c5c-ad8266bfbc73" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_DocumentType"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019e41f4-826b-7e97-91dc-07f7704191db" xlink:to="loc_dei_DocumentType_019e41f4-826b-7a51-8c5c-ad8266bfbc73" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentQuarterlyReport_019e41f4-826b-7bb7-807f-4c8473939955" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_DocumentQuarterlyReport"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019e41f4-826b-7e97-91dc-07f7704191db" xlink:to="loc_dei_DocumentQuarterlyReport_019e41f4-826b-7bb7-807f-4c8473939955" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentPeriodEndDate_019e41f4-826b-7045-8e49-33a479e784d7" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_DocumentPeriodEndDate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019e41f4-826b-7e97-91dc-07f7704191db" xlink:to="loc_dei_DocumentPeriodEndDate_019e41f4-826b-7045-8e49-33a479e784d7" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentTransitionReport_019e41f4-826b-7a58-8243-2ee4fd3da817" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_DocumentTransitionReport"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019e41f4-826b-7e97-91dc-07f7704191db" xlink:to="loc_dei_DocumentTransitionReport_019e41f4-826b-7a58-8243-2ee4fd3da817" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityRegistrantName_019e41f4-826b-7d6b-8f67-b67df8a27fb3" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityRegistrantName"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019e41f4-826b-7e97-91dc-07f7704191db" xlink:to="loc_dei_EntityRegistrantName_019e41f4-826b-7d6b-8f67-b67df8a27fb3" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityIncorporationStateCountryCode_019e41f4-826b-7b9d-a2f2-463527959084" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityIncorporationStateCountryCode"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019e41f4-826b-7e97-91dc-07f7704191db" xlink:to="loc_dei_EntityIncorporationStateCountryCode_019e41f4-826b-7b9d-a2f2-463527959084" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityFileNumber_019e41f4-826b-70cd-aa3a-56d5492d7b3a" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityFileNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019e41f4-826b-7e97-91dc-07f7704191db" xlink:to="loc_dei_EntityFileNumber_019e41f4-826b-70cd-aa3a-56d5492d7b3a" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityTaxIdentificationNumber_019e41f4-826b-7973-95a3-b76a7f2f33ce" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityTaxIdentificationNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019e41f4-826b-7e97-91dc-07f7704191db" xlink:to="loc_dei_EntityTaxIdentificationNumber_019e41f4-826b-7973-95a3-b76a7f2f33ce" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressAddressLine1_019e41f4-826b-7db5-996f-0209d99b7ba3" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityAddressAddressLine1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019e41f4-826b-7e97-91dc-07f7704191db" xlink:to="loc_dei_EntityAddressAddressLine1_019e41f4-826b-7db5-996f-0209d99b7ba3" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressCityOrTown_019e41f4-826b-78a5-8105-bf6a360837af" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityAddressCityOrTown"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019e41f4-826b-7e97-91dc-07f7704191db" xlink:to="loc_dei_EntityAddressCityOrTown_019e41f4-826b-78a5-8105-bf6a360837af" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressStateOrProvince_019e41f4-826b-7c6d-933a-314585dff5df" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityAddressStateOrProvince"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019e41f4-826b-7e97-91dc-07f7704191db" xlink:to="loc_dei_EntityAddressStateOrProvince_019e41f4-826b-7c6d-933a-314585dff5df" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressPostalZipCode_019e41f4-826b-71e9-a3ec-79b139e1b382" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityAddressPostalZipCode"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019e41f4-826b-7e97-91dc-07f7704191db" xlink:to="loc_dei_EntityAddressPostalZipCode_019e41f4-826b-71e9-a3ec-79b139e1b382" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_CityAreaCode_019e41f4-826b-7060-8e67-4daa8e0818d8" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_CityAreaCode"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019e41f4-826b-7e97-91dc-07f7704191db" xlink:to="loc_dei_CityAreaCode_019e41f4-826b-7060-8e67-4daa8e0818d8" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_LocalPhoneNumber_019e41f4-826b-7685-a3fb-4048b8850d97" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_LocalPhoneNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019e41f4-826b-7e97-91dc-07f7704191db" xlink:to="loc_dei_LocalPhoneNumber_019e41f4-826b-7685-a3fb-4048b8850d97" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_Security12bTitle_019e41f4-826b-7b6c-aacd-a0b2ddf21e5b" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_Security12bTitle"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019e41f4-826b-7e97-91dc-07f7704191db" xlink:to="loc_dei_Security12bTitle_019e41f4-826b-7b6c-aacd-a0b2ddf21e5b" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_TradingSymbol_019e41f4-826b-746c-ba61-121aa1e9113f" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_TradingSymbol"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019e41f4-826b-7e97-91dc-07f7704191db" xlink:to="loc_dei_TradingSymbol_019e41f4-826b-746c-ba61-121aa1e9113f" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_SecurityExchangeName_019e41f4-826b-78be-9baf-96ca05fa0ec0" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_SecurityExchangeName"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019e41f4-826b-7e97-91dc-07f7704191db" xlink:to="loc_dei_SecurityExchangeName_019e41f4-826b-78be-9baf-96ca05fa0ec0" xlink:type="arc" order="16"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityCurrentReportingStatus_019e41f4-826b-7c0e-8d38-48488eb34381" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityCurrentReportingStatus"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019e41f4-826b-7e97-91dc-07f7704191db" xlink:to="loc_dei_EntityCurrentReportingStatus_019e41f4-826b-7c0e-8d38-48488eb34381" xlink:type="arc" order="17"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityInteractiveDataCurrent_019e41f4-826b-7385-a77c-3fdcdc8387f1" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityInteractiveDataCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019e41f4-826b-7e97-91dc-07f7704191db" xlink:to="loc_dei_EntityInteractiveDataCurrent_019e41f4-826b-7385-a77c-3fdcdc8387f1" xlink:type="arc" order="18"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityFilerCategory_019e41f4-826b-742f-bb92-d7a88e7c9a29" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityFilerCategory"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019e41f4-826b-7e97-91dc-07f7704191db" xlink:to="loc_dei_EntityFilerCategory_019e41f4-826b-742f-bb92-d7a88e7c9a29" xlink:type="arc" order="19"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntitySmallBusiness_019e41f4-826b-7f0f-9e5c-8623268b9093" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntitySmallBusiness"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019e41f4-826b-7e97-91dc-07f7704191db" xlink:to="loc_dei_EntitySmallBusiness_019e41f4-826b-7f0f-9e5c-8623268b9093" xlink:type="arc" order="20"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityEmergingGrowthCompany_019e41f4-826b-70e0-8640-6d4a57e64c36" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityEmergingGrowthCompany"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019e41f4-826b-7e97-91dc-07f7704191db" xlink:to="loc_dei_EntityEmergingGrowthCompany_019e41f4-826b-70e0-8640-6d4a57e64c36" xlink:type="arc" order="21"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityShellCompany_019e41f4-826b-71f5-b1ce-d628bab2a874" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityShellCompany"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019e41f4-826b-7e97-91dc-07f7704191db" xlink:to="loc_dei_EntityShellCompany_019e41f4-826b-71f5-b1ce-d628bab2a874" xlink:type="arc" order="22"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityCommonStockSharesOutstanding_019e41f4-826b-7ee7-8ec5-455cac577ee3" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityCommonStockSharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019e41f4-826b-7e97-91dc-07f7704191db" xlink:to="loc_dei_EntityCommonStockSharesOutstanding_019e41f4-826b-7ee7-8ec5-455cac577ee3" xlink:type="arc" order="23"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityCentralIndexKey_019e41f4-826b-7db3-8966-a8ac9b321422" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityCentralIndexKey"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019e41f4-826b-7e97-91dc-07f7704191db" xlink:to="loc_dei_EntityCentralIndexKey_019e41f4-826b-7db3-8966-a8ac9b321422" xlink:type="arc" order="24"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_CurrentFiscalYearEndDate_019e41f4-826b-7510-8faa-c45c41cb703d" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_CurrentFiscalYearEndDate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019e41f4-826b-7e97-91dc-07f7704191db" xlink:to="loc_dei_CurrentFiscalYearEndDate_019e41f4-826b-7510-8faa-c45c41cb703d" xlink:type="arc" order="25"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentFiscalYearFocus_019e41f4-826b-7569-a30a-d623490303d7" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_DocumentFiscalYearFocus"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019e41f4-826b-7e97-91dc-07f7704191db" xlink:to="loc_dei_DocumentFiscalYearFocus_019e41f4-826b-7569-a30a-d623490303d7" xlink:type="arc" order="26"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentFiscalPeriodFocus_019e41f4-826b-78bb-a93d-8cecf587dcf1" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_DocumentFiscalPeriodFocus"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019e41f4-826b-7e97-91dc-07f7704191db" xlink:to="loc_dei_DocumentFiscalPeriodFocus_019e41f4-826b-78bb-a93d-8cecf587dcf1" xlink:type="arc" order="27"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_AmendmentFlag_019e41f4-826b-7540-81ea-33ac1f8849fc" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_AmendmentFlag"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019e41f4-826b-7e97-91dc-07f7704191db" xlink:to="loc_dei_AmendmentFlag_019e41f4-826b-7540-81ea-33ac1f8849fc" xlink:type="arc" order="28"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.firstmerchants.com/role/CONSOLIDATEDCONDENSEDBALANCESHEETSUnaudited" xlink:type="simple" xlink:href="frme-20260630.xsd#CONSOLIDATEDCONDENSEDBALANCESHEETSUnaudited"/>
  <link:definitionLink xlink:role="http://www.firstmerchants.com/role/CONSOLIDATEDCONDENSEDBALANCESHEETSUnaudited" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_019e41f4-826b-76ef-bfc8-1bae364cc32f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_019e41f4-826b-7ca9-a059-8f6505050b7d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_019e41f4-826b-76ef-bfc8-1bae364cc32f" xlink:to="loc_us-gaap_StatementTable_019e41f4-826b-7ca9-a059-8f6505050b7d" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementClassOfStockAxis_019e41f4-826b-70e6-b701-016bc5a69c08" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementClassOfStockAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_019e41f4-826b-7ca9-a059-8f6505050b7d" xlink:to="loc_us-gaap_StatementClassOfStockAxis_019e41f4-826b-70e6-b701-016bc5a69c08" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_019e41f4-826b-70e6-b701-016bc5a69c08_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_019e41f4-826b-70e6-b701-016bc5a69c08" xlink:to="loc_us-gaap_ClassOfStockDomain_019e41f4-826b-70e6-b701-016bc5a69c08_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_019e41f4-826b-7c94-aaa6-9462350785c7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_019e41f4-826b-70e6-b701-016bc5a69c08" xlink:to="loc_us-gaap_ClassOfStockDomain_019e41f4-826b-7c94-aaa6-9462350785c7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CumulativePreferredStockMember_019e41f4-826b-70ac-88aa-a689dad29937" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CumulativePreferredStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_019e41f4-826b-7c94-aaa6-9462350785c7" xlink:to="loc_us-gaap_CumulativePreferredStockMember_019e41f4-826b-70ac-88aa-a689dad29937" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SeriesAPreferredStockMember_019e41f4-826b-7c97-aef0-4adaea59ec63" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SeriesAPreferredStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_019e41f4-826b-7c94-aaa6-9462350785c7" xlink:to="loc_us-gaap_SeriesAPreferredStockMember_019e41f4-826b-7c97-aef0-4adaea59ec63" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsAbstract_019e41f4-826b-7129-8bac-09ec2024daf4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetsAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e41f4-826b-76ef-bfc8-1bae364cc32f" xlink:to="loc_us-gaap_AssetsAbstract_019e41f4-826b-7129-8bac-09ec2024daf4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndDueFromBanks_019e41f4-826b-725a-b455-c81a9cb785b5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CashAndDueFromBanks"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_019e41f4-826b-7129-8bac-09ec2024daf4" xlink:to="loc_us-gaap_CashAndDueFromBanks_019e41f4-826b-725a-b455-c81a9cb785b5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestBearingDepositsInBanks_019e41f4-826b-7e6e-8c6f-a1541e9fe978" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestBearingDepositsInBanks"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_019e41f4-826b-7129-8bac-09ec2024daf4" xlink:to="loc_us-gaap_InterestBearingDepositsInBanks_019e41f4-826b-7e6e-8c6f-a1541e9fe978" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleExcludingAccruedInterest_019e41f4-826b-7d83-b0f7-578c7f34461d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtSecuritiesAvailableForSaleExcludingAccruedInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_019e41f4-826b-7129-8bac-09ec2024daf4" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleExcludingAccruedInterest_019e41f4-826b-7d83-b0f7-578c7f34461d" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesHeldToMaturityExcludingAccruedInterestAfterAllowanceForCreditLoss_019e41f4-826b-74aa-b45e-56f64a774ac6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtSecuritiesHeldToMaturityExcludingAccruedInterestAfterAllowanceForCreditLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_019e41f4-826b-7129-8bac-09ec2024daf4" xlink:to="loc_us-gaap_DebtSecuritiesHeldToMaturityExcludingAccruedInterestAfterAllowanceForCreditLoss_019e41f4-826b-74aa-b45e-56f64a774ac6" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LoansReceivableHeldForSaleAmount_019e41f4-826b-7542-aa05-00c17139bef1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LoansReceivableHeldForSaleAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_019e41f4-826b-7129-8bac-09ec2024daf4" xlink:to="loc_us-gaap_LoansReceivableHeldForSaleAmount_019e41f4-826b-7542-aa05-00c17139bef1" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss_019e41f4-826b-7d6d-b32f-1a0bacc4bff2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_019e41f4-826b-7129-8bac-09ec2024daf4" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss_019e41f4-826b-7d6d-b32f-1a0bacc4bff2" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest_019e41f4-826b-7e2f-b2b1-17904a6ba647" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_019e41f4-826b-7129-8bac-09ec2024daf4" xlink:to="loc_us-gaap_FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest_019e41f4-826b-7e2f-b2b1-17904a6ba647" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestAfterAllowanceForCreditLoss_019e41f4-826b-7311-bf95-b7448dd8ad1e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestAfterAllowanceForCreditLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_019e41f4-826b-7129-8bac-09ec2024daf4" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestAfterAllowanceForCreditLoss_019e41f4-826b-7311-bf95-b7448dd8ad1e" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentNet_019e41f4-826b-7279-9ae9-55fd1c78ef95" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyPlantAndEquipmentNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_019e41f4-826b-7129-8bac-09ec2024daf4" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentNet_019e41f4-826b-7279-9ae9-55fd1c78ef95" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FederalHomeLoanBankStock_019e41f4-826b-72d5-99c3-b0d563c286dd" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FederalHomeLoanBankStock"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_019e41f4-826b-7129-8bac-09ec2024daf4" xlink:to="loc_us-gaap_FederalHomeLoanBankStock_019e41f4-826b-72d5-99c3-b0d563c286dd" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestReceivable_019e41f4-826b-73b8-80d5-ee18f042a19d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestReceivable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_019e41f4-826b-7129-8bac-09ec2024daf4" xlink:to="loc_us-gaap_InterestReceivable_019e41f4-826b-73b8-80d5-ee18f042a19d" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Goodwill_019e41f4-826b-7f01-a596-7b77f3007154" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_Goodwill"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_019e41f4-826b-7129-8bac-09ec2024daf4" xlink:to="loc_us-gaap_Goodwill_019e41f4-826b-7f01-a596-7b77f3007154" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IntangibleAssetsNetExcludingGoodwill_019e41f4-826b-7866-91b9-b8c73ab1729e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IntangibleAssetsNetExcludingGoodwill"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_019e41f4-826b-7129-8bac-09ec2024daf4" xlink:to="loc_us-gaap_IntangibleAssetsNetExcludingGoodwill_019e41f4-826b-7866-91b9-b8c73ab1729e" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashSurrenderValueOfLifeInsurance_019e41f4-826b-7eb7-b3da-26d08ded8b92" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CashSurrenderValueOfLifeInsurance"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_019e41f4-826b-7129-8bac-09ec2024daf4" xlink:to="loc_us-gaap_CashSurrenderValueOfLifeInsurance_019e41f4-826b-7eb7-b3da-26d08ded8b92" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealEstateAcquiredThroughForeclosure_019e41f4-826b-79e0-a26e-d79bba0d1bc6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RealEstateAcquiredThroughForeclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_019e41f4-826b-7129-8bac-09ec2024daf4" xlink:to="loc_us-gaap_RealEstateAcquiredThroughForeclosure_019e41f4-826b-79e0-a26e-d79bba0d1bc6" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredIncomeTaxAssetsNet_019e41f4-826b-7089-ae80-b5512029b585" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DeferredIncomeTaxAssetsNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_019e41f4-826b-7129-8bac-09ec2024daf4" xlink:to="loc_us-gaap_DeferredIncomeTaxAssetsNet_019e41f4-826b-7089-ae80-b5512029b585" xlink:type="arc" order="16"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherAssets_019e41f4-826b-7e0e-ace1-05a00c0ec95a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_019e41f4-826b-7129-8bac-09ec2024daf4" xlink:to="loc_us-gaap_OtherAssets_019e41f4-826b-7e0e-ace1-05a00c0ec95a" xlink:type="arc" order="17"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Assets_019e41f4-826b-7cb4-9dfe-f3ff40f8099a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_Assets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_019e41f4-826b-7129-8bac-09ec2024daf4" xlink:to="loc_us-gaap_Assets_019e41f4-826b-7cb4-9dfe-f3ff40f8099a" xlink:type="arc" order="18"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesAbstract_019e41f4-826b-76cb-9021-3f0594472165" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LiabilitiesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e41f4-826b-76ef-bfc8-1bae364cc32f" xlink:to="loc_us-gaap_LiabilitiesAbstract_019e41f4-826b-76cb-9021-3f0594472165" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DepositsAbstract_019e41f4-826b-7300-adaa-516e7f349718" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DepositsAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAbstract_019e41f4-826b-76cb-9021-3f0594472165" xlink:to="loc_us-gaap_DepositsAbstract_019e41f4-826b-7300-adaa-516e7f349718" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NoninterestBearingDepositLiabilities_019e41f4-826b-7906-b423-b8eb65f1ec36" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NoninterestBearingDepositLiabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DepositsAbstract_019e41f4-826b-7300-adaa-516e7f349718" xlink:to="loc_us-gaap_NoninterestBearingDepositLiabilities_019e41f4-826b-7906-b423-b8eb65f1ec36" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestBearingDepositLiabilities_019e41f4-826b-7827-9a49-2f25de296f9a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestBearingDepositLiabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DepositsAbstract_019e41f4-826b-7300-adaa-516e7f349718" xlink:to="loc_us-gaap_InterestBearingDepositLiabilities_019e41f4-826b-7827-9a49-2f25de296f9a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Deposits_019e41f4-826b-7ac5-8433-b5b03de9b0b9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_Deposits"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DepositsAbstract_019e41f4-826b-7300-adaa-516e7f349718" xlink:to="loc_us-gaap_Deposits_019e41f4-826b-7ac5-8433-b5b03de9b0b9" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_BorrowedFundsAbstract_019e41f4-826b-7df2-8822-44cb97622624" xlink:href="frme-20260630.xsd#frme_BorrowedFundsAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAbstract_019e41f4-826b-76cb-9021-3f0594472165" xlink:to="loc_frme_BorrowedFundsAbstract_019e41f4-826b-7df2-8822-44cb97622624" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FederalFundsPurchased_019e41f4-826b-7b1d-9df2-1beca2891fc1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FederalFundsPurchased"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_frme_BorrowedFundsAbstract_019e41f4-826b-7df2-8822-44cb97622624" xlink:to="loc_us-gaap_FederalFundsPurchased_019e41f4-826b-7b1d-9df2-1beca2891fc1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SecuritiesSoldUnderAgreementsToRepurchase_019e41f4-826b-7a00-ab1b-56e51ff3b235" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SecuritiesSoldUnderAgreementsToRepurchase"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_frme_BorrowedFundsAbstract_019e41f4-826b-7df2-8822-44cb97622624" xlink:to="loc_us-gaap_SecuritiesSoldUnderAgreementsToRepurchase_019e41f4-826b-7a00-ab1b-56e51ff3b235" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdvancesFromFederalHomeLoanBanks_019e41f4-826b-727f-9320-e6b2e6ab20ff" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AdvancesFromFederalHomeLoanBanks"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_frme_BorrowedFundsAbstract_019e41f4-826b-7df2-8822-44cb97622624" xlink:to="loc_us-gaap_AdvancesFromFederalHomeLoanBanks_019e41f4-826b-727f-9320-e6b2e6ab20ff" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherBorrowings_019e41f4-826b-7bb7-b07d-9e5a64902e0a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherBorrowings"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_frme_BorrowedFundsAbstract_019e41f4-826b-7df2-8822-44cb97622624" xlink:to="loc_us-gaap_OtherBorrowings_019e41f4-826b-7bb7-b07d-9e5a64902e0a" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtLongtermAndShorttermCombinedAmount_019e41f4-826b-7e6b-8cca-1f859e392b20" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtLongtermAndShorttermCombinedAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_frme_BorrowedFundsAbstract_019e41f4-826b-7df2-8822-44cb97622624" xlink:to="loc_us-gaap_DebtLongtermAndShorttermCombinedAmount_019e41f4-826b-7e6b-8cca-1f859e392b20" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestPayableCurrentAndNoncurrent_019e41f4-826b-79ae-aa70-08db1672a2f6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestPayableCurrentAndNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAbstract_019e41f4-826b-76cb-9021-3f0594472165" xlink:to="loc_us-gaap_InterestPayableCurrentAndNoncurrent_019e41f4-826b-79ae-aa70-08db1672a2f6" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherLiabilities_019e41f4-826b-7c3c-9f9c-f9e7f046a981" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherLiabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAbstract_019e41f4-826b-76cb-9021-3f0594472165" xlink:to="loc_us-gaap_OtherLiabilities_019e41f4-826b-7c3c-9f9c-f9e7f046a981" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Liabilities_019e41f4-826b-78d9-ba08-6cd12c20a6f8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_Liabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAbstract_019e41f4-826b-76cb-9021-3f0594472165" xlink:to="loc_us-gaap_Liabilities_019e41f4-826b-78d9-ba08-6cd12c20a6f8" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommitmentsAndContingencies_019e41f4-826b-7c0c-a842-cdcb162d54ef" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommitmentsAndContingencies"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e41f4-826b-76ef-bfc8-1bae364cc32f" xlink:to="loc_us-gaap_CommitmentsAndContingencies_019e41f4-826b-7c0c-a842-cdcb162d54ef" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityAbstract_019e41f4-826b-7584-ad15-6f421efc434a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockholdersEquityAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e41f4-826b-76ef-bfc8-1bae364cc32f" xlink:to="loc_us-gaap_StockholdersEquityAbstract_019e41f4-826b-7584-ad15-6f421efc434a" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockValue_019e41f4-826b-7050-b5ac-8e73fbf3de32" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PreferredStockValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_019e41f4-826b-7584-ad15-6f421efc434a" xlink:to="loc_us-gaap_PreferredStockValue_019e41f4-826b-7050-b5ac-8e73fbf3de32" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockValue_019e41f4-826b-767b-ae37-ec382f5cac14" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_019e41f4-826b-7584-ad15-6f421efc434a" xlink:to="loc_us-gaap_CommonStockValue_019e41f4-826b-767b-ae37-ec382f5cac14" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdditionalPaidInCapital_019e41f4-826b-7cb7-9df7-c365572d9f7d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AdditionalPaidInCapital"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_019e41f4-826b-7584-ad15-6f421efc434a" xlink:to="loc_us-gaap_AdditionalPaidInCapital_019e41f4-826b-7cb7-9df7-c365572d9f7d" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetainedEarningsAccumulatedDeficit_019e41f4-826b-7b56-b043-12d2b4899a2b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RetainedEarningsAccumulatedDeficit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_019e41f4-826b-7584-ad15-6f421efc434a" xlink:to="loc_us-gaap_RetainedEarningsAccumulatedDeficit_019e41f4-826b-7b56-b043-12d2b4899a2b" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_019e41f4-826b-78dc-ac55-10ffae43559a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_019e41f4-826b-7584-ad15-6f421efc434a" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_019e41f4-826b-78dc-ac55-10ffae43559a" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_019e41f4-826b-7733-bde5-ac409f740e76" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockholdersEquity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_019e41f4-826b-7584-ad15-6f421efc434a" xlink:to="loc_us-gaap_StockholdersEquity_019e41f4-826b-7733-bde5-ac409f740e76" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquity_019e41f4-826b-7822-b8f4-875d271fded4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LiabilitiesAndStockholdersEquity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e41f4-826b-76ef-bfc8-1bae364cc32f" xlink:to="loc_us-gaap_LiabilitiesAndStockholdersEquity_019e41f4-826b-7822-b8f4-875d271fded4" xlink:type="arc" order="4"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.firstmerchants.com/role/CONSOLIDATEDCONDENSEDBALANCESHEETSUnauditedParenthetical" xlink:type="simple" xlink:href="frme-20260630.xsd#CONSOLIDATEDCONDENSEDBALANCESHEETSUnauditedParenthetical"/>
  <link:definitionLink xlink:role="http://www.firstmerchants.com/role/CONSOLIDATEDCONDENSEDBALANCESHEETSUnauditedParenthetical" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_019e41f4-826b-7931-8118-640f9d34b7a9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_019e41f4-826b-78ad-9862-10f783b3ba4c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_019e41f4-826b-7931-8118-640f9d34b7a9" xlink:to="loc_us-gaap_StatementTable_019e41f4-826b-78ad-9862-10f783b3ba4c" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementClassOfStockAxis_019e41f4-826b-7cd9-89dc-dba851671f89" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementClassOfStockAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_019e41f4-826b-78ad-9862-10f783b3ba4c" xlink:to="loc_us-gaap_StatementClassOfStockAxis_019e41f4-826b-7cd9-89dc-dba851671f89" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_019e41f4-826b-7cd9-89dc-dba851671f89_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_019e41f4-826b-7cd9-89dc-dba851671f89" xlink:to="loc_us-gaap_ClassOfStockDomain_019e41f4-826b-7cd9-89dc-dba851671f89_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_019e41f4-826b-723d-b4b1-8207b5e79a50" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_019e41f4-826b-7cd9-89dc-dba851671f89" xlink:to="loc_us-gaap_ClassOfStockDomain_019e41f4-826b-723d-b4b1-8207b5e79a50" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CumulativePreferredStockMember_019e41f4-826b-7d67-a635-ee4617bda74c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CumulativePreferredStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_019e41f4-826b-723d-b4b1-8207b5e79a50" xlink:to="loc_us-gaap_CumulativePreferredStockMember_019e41f4-826b-7d67-a635-ee4617bda74c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SeriesAPreferredStockMember_019e41f4-826b-7ba2-8166-0f908a9adb56" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SeriesAPreferredStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_019e41f4-826b-723d-b4b1-8207b5e79a50" xlink:to="loc_us-gaap_SeriesAPreferredStockMember_019e41f4-826b-7ba2-8166-0f908a9adb56" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesHeldToMaturityAllowanceForCreditLossExcludingAccruedInterest_019e41f4-826b-7d4b-a949-7d0c50afb967" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtSecuritiesHeldToMaturityAllowanceForCreditLossExcludingAccruedInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e41f4-826b-7931-8118-640f9d34b7a9" xlink:to="loc_us-gaap_DebtSecuritiesHeldToMaturityAllowanceForCreditLossExcludingAccruedInterest_019e41f4-826b-7d4b-a949-7d0c50afb967" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HeldToMaturitySecuritiesFairValue_019e41f4-826b-7b58-a252-69c03b090656" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_HeldToMaturitySecuritiesFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e41f4-826b-7931-8118-640f9d34b7a9" xlink:to="loc_us-gaap_HeldToMaturitySecuritiesFairValue_019e41f4-826b-7b58-a252-69c03b090656" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockParOrStatedValuePerShare_019e41f4-826b-748d-92d5-3bc9a409b883" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PreferredStockParOrStatedValuePerShare"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e41f4-826b-7931-8118-640f9d34b7a9" xlink:to="loc_us-gaap_PreferredStockParOrStatedValuePerShare_019e41f4-826b-748d-92d5-3bc9a409b883" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockLiquidationPreference_019e41f4-826b-7cd4-8027-da4c6de5addc" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PreferredStockLiquidationPreference"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e41f4-826b-7931-8118-640f9d34b7a9" xlink:to="loc_us-gaap_PreferredStockLiquidationPreference_019e41f4-826b-7cd4-8027-da4c6de5addc" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockSharesAuthorized_019e41f4-826b-7a5b-93c9-36897c0bd837" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PreferredStockSharesAuthorized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e41f4-826b-7931-8118-640f9d34b7a9" xlink:to="loc_us-gaap_PreferredStockSharesAuthorized_019e41f4-826b-7a5b-93c9-36897c0bd837" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockSharesIssued_019e41f4-826b-7eae-816e-129a71f78354" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PreferredStockSharesIssued"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e41f4-826b-7931-8118-640f9d34b7a9" xlink:to="loc_us-gaap_PreferredStockSharesIssued_019e41f4-826b-7eae-816e-129a71f78354" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockSharesOutstanding_019e41f4-826b-7d60-a358-61a50c489d3a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PreferredStockSharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e41f4-826b-7931-8118-640f9d34b7a9" xlink:to="loc_us-gaap_PreferredStockSharesOutstanding_019e41f4-826b-7d60-a358-61a50c489d3a" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockParOrStatedValuePerShare_019e41f4-826b-7127-8746-2818b1eb4fc9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockParOrStatedValuePerShare"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e41f4-826b-7931-8118-640f9d34b7a9" xlink:to="loc_us-gaap_CommonStockParOrStatedValuePerShare_019e41f4-826b-7127-8746-2818b1eb4fc9" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesAuthorized_019e41f4-826b-7a8b-baf1-495990f65a23" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockSharesAuthorized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e41f4-826b-7931-8118-640f9d34b7a9" xlink:to="loc_us-gaap_CommonStockSharesAuthorized_019e41f4-826b-7a8b-baf1-495990f65a23" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesIssued_019e41f4-826b-7125-9f58-9f9b45ed549d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockSharesIssued"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e41f4-826b-7931-8118-640f9d34b7a9" xlink:to="loc_us-gaap_CommonStockSharesIssued_019e41f4-826b-7125-9f58-9f9b45ed549d" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesOutstanding_019e41f4-826b-7a3d-94fd-1a8e5a17a3ae" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockSharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e41f4-826b-7931-8118-640f9d34b7a9" xlink:to="loc_us-gaap_CommonStockSharesOutstanding_019e41f4-826b-7a3d-94fd-1a8e5a17a3ae" xlink:type="arc" order="10"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.firstmerchants.com/role/CONSOLIDATEDCONDENSEDSTATEMENTSOFINCOMEUnaudited" xlink:type="simple" xlink:href="frme-20260630.xsd#CONSOLIDATEDCONDENSEDSTATEMENTSOFINCOMEUnaudited"/>
  <link:definitionLink xlink:role="http://www.firstmerchants.com/role/CONSOLIDATEDCONDENSEDSTATEMENTSOFINCOMEUnaudited" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_019e41f4-826b-7867-9bd7-9064c971a8dc" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_019e41f4-826b-7000-bf12-4a0b0f64d0cd" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_019e41f4-826b-7867-9bd7-9064c971a8dc" xlink:to="loc_us-gaap_StatementTable_019e41f4-826b-7000-bf12-4a0b0f64d0cd" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_019e41f4-826b-73a1-9fb3-0a7aa66594bf" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ProductOrServiceAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_019e41f4-826b-7000-bf12-4a0b0f64d0cd" xlink:to="loc_srt_ProductOrServiceAxis_019e41f4-826b-73a1-9fb3-0a7aa66594bf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_019e41f4-826b-73a1-9fb3-0a7aa66594bf_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_019e41f4-826b-73a1-9fb3-0a7aa66594bf" xlink:to="loc_srt_ProductsAndServicesDomain_019e41f4-826b-73a1-9fb3-0a7aa66594bf_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_019e41f4-826b-7dec-9782-f92e5e576931" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_019e41f4-826b-73a1-9fb3-0a7aa66594bf" xlink:to="loc_srt_ProductsAndServicesDomain_019e41f4-826b-7dec-9782-f92e5e576931" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DepositAccountMember_019e41f4-826b-7e83-a720-e49c816e61c0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DepositAccountMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_019e41f4-826b-7dec-9782-f92e5e576931" xlink:to="loc_us-gaap_DepositAccountMember_019e41f4-826b-7e83-a720-e49c816e61c0" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiduciaryAndTrustMember_019e41f4-826b-7ecb-b9af-ac4a750aeb88" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FiduciaryAndTrustMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_019e41f4-826b-7dec-9782-f92e5e576931" xlink:to="loc_us-gaap_FiduciaryAndTrustMember_019e41f4-826b-7ecb-b9af-ac4a750aeb88" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditCardMember_019e41f4-826b-7696-8779-0dcd2f1def82" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CreditCardMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_019e41f4-826b-7dec-9782-f92e5e576931" xlink:to="loc_us-gaap_CreditCardMember_019e41f4-826b-7696-8779-0dcd2f1def82" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_DerivativeHedgingMember_019e41f4-826b-72f5-870b-e686decea736" xlink:href="frme-20260630.xsd#frme_DerivativeHedgingMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_019e41f4-826b-7dec-9782-f92e5e576931" xlink:to="loc_frme_DerivativeHedgingMember_019e41f4-826b-72f5-870b-e686decea736" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialServiceOtherMember_019e41f4-826b-78cb-8980-2a7d1397f868" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancialServiceOtherMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_019e41f4-826b-7dec-9782-f92e5e576931" xlink:to="loc_us-gaap_FinancialServiceOtherMember_019e41f4-826b-78cb-8980-2a7d1397f868" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestAndDividendIncomeOperatingAbstract_019e41f4-826b-7101-a8e9-fce28a3551d8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestAndDividendIncomeOperatingAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e41f4-826b-7867-9bd7-9064c971a8dc" xlink:to="loc_us-gaap_InterestAndDividendIncomeOperatingAbstract_019e41f4-826b-7101-a8e9-fce28a3551d8" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestAndFeeIncomeLoansAndLeasesAbstract_019e41f4-826b-75c5-be14-55b173adb225" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestAndFeeIncomeLoansAndLeasesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InterestAndDividendIncomeOperatingAbstract_019e41f4-826b-7101-a8e9-fce28a3551d8" xlink:to="loc_us-gaap_InterestAndFeeIncomeLoansAndLeasesAbstract_019e41f4-826b-75c5-be14-55b173adb225" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_InterestAndFeeIncomeLoansAndLeasesTaxable_019e41f4-826b-7687-9c3c-1c52581ed56a" xlink:href="frme-20260630.xsd#frme_InterestAndFeeIncomeLoansAndLeasesTaxable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InterestAndFeeIncomeLoansAndLeasesAbstract_019e41f4-826b-75c5-be14-55b173adb225" xlink:to="loc_frme_InterestAndFeeIncomeLoansAndLeasesTaxable_019e41f4-826b-7687-9c3c-1c52581ed56a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_InterestAndFeeIncomeLoansAndLeasesTaxExempt_019e41f4-826b-7bb5-aa83-3416b12ee575" xlink:href="frme-20260630.xsd#frme_InterestAndFeeIncomeLoansAndLeasesTaxExempt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InterestAndFeeIncomeLoansAndLeasesAbstract_019e41f4-826b-75c5-be14-55b173adb225" xlink:to="loc_frme_InterestAndFeeIncomeLoansAndLeasesTaxExempt_019e41f4-826b-7bb5-aa83-3416b12ee575" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestAndDividendIncomeSecuritiesByTaxableStatusAbstract_019e41f4-826b-7719-843a-e5bbc1fe5630" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestAndDividendIncomeSecuritiesByTaxableStatusAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InterestAndDividendIncomeOperatingAbstract_019e41f4-826b-7101-a8e9-fce28a3551d8" xlink:to="loc_us-gaap_InterestAndDividendIncomeSecuritiesByTaxableStatusAbstract_019e41f4-826b-7719-843a-e5bbc1fe5630" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestIncomeSecuritiesTaxable_019e41f4-826b-7527-b861-ae1e20019b62" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestIncomeSecuritiesTaxable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InterestAndDividendIncomeSecuritiesByTaxableStatusAbstract_019e41f4-826b-7719-843a-e5bbc1fe5630" xlink:to="loc_us-gaap_InterestIncomeSecuritiesTaxable_019e41f4-826b-7527-b861-ae1e20019b62" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestIncomeSecuritiesTaxExempt_019e41f4-826b-732b-b1ba-ab3fe0cccf4a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestIncomeSecuritiesTaxExempt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InterestAndDividendIncomeSecuritiesByTaxableStatusAbstract_019e41f4-826b-7719-843a-e5bbc1fe5630" xlink:to="loc_us-gaap_InterestIncomeSecuritiesTaxExempt_019e41f4-826b-732b-b1ba-ab3fe0cccf4a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestIncomeDepositsWithFinancialInstitutions_019e41f4-826b-70f3-a6e2-78b12bed993e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestIncomeDepositsWithFinancialInstitutions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InterestAndDividendIncomeOperatingAbstract_019e41f4-826b-7101-a8e9-fce28a3551d8" xlink:to="loc_us-gaap_InterestIncomeDepositsWithFinancialInstitutions_019e41f4-826b-70f3-a6e2-78b12bed993e" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_InterestIncomeFederalHomeLoanBankStock_019e41f4-826b-7d96-bd38-27b261f2e4ec" xlink:href="frme-20260630.xsd#frme_InterestIncomeFederalHomeLoanBankStock"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InterestAndDividendIncomeOperatingAbstract_019e41f4-826b-7101-a8e9-fce28a3551d8" xlink:to="loc_frme_InterestIncomeFederalHomeLoanBankStock_019e41f4-826b-7d96-bd38-27b261f2e4ec" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestAndDividendIncomeOperating_019e41f4-826b-7e63-a222-9a8f4becfcab" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestAndDividendIncomeOperating"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InterestAndDividendIncomeOperatingAbstract_019e41f4-826b-7101-a8e9-fce28a3551d8" xlink:to="loc_us-gaap_InterestAndDividendIncomeOperating_019e41f4-826b-7e63-a222-9a8f4becfcab" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestExpenseAbstract_019e41f4-826b-7287-aff5-8fcb5e24be4c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestExpenseAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e41f4-826b-7867-9bd7-9064c971a8dc" xlink:to="loc_us-gaap_InterestExpenseAbstract_019e41f4-826b-7287-aff5-8fcb5e24be4c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestExpenseDeposits_019e41f4-826b-795a-aa01-1cf6f1df87ff" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestExpenseDeposits"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InterestExpenseAbstract_019e41f4-826b-7287-aff5-8fcb5e24be4c" xlink:to="loc_us-gaap_InterestExpenseDeposits_019e41f4-826b-795a-aa01-1cf6f1df87ff" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestExpenseFederalFundsPurchased_019e41f4-826b-7845-a56a-71c818e04237" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestExpenseFederalFundsPurchased"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InterestExpenseAbstract_019e41f4-826b-7287-aff5-8fcb5e24be4c" xlink:to="loc_us-gaap_InterestExpenseFederalFundsPurchased_019e41f4-826b-7845-a56a-71c818e04237" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestExpenseSecuritiesSoldUnderAgreementsToRepurchase_019e41f4-826b-7f3e-a3bd-4f426261c012" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestExpenseSecuritiesSoldUnderAgreementsToRepurchase"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InterestExpenseAbstract_019e41f4-826b-7287-aff5-8fcb5e24be4c" xlink:to="loc_us-gaap_InterestExpenseSecuritiesSoldUnderAgreementsToRepurchase_019e41f4-826b-7f3e-a3bd-4f426261c012" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestExpenseFederalHomeLoanBankAndFederalReserveBankAdvancesLongTerm_019e41f4-826b-7cb4-b0d3-52889c3fc966" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestExpenseFederalHomeLoanBankAndFederalReserveBankAdvancesLongTerm"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InterestExpenseAbstract_019e41f4-826b-7287-aff5-8fcb5e24be4c" xlink:to="loc_us-gaap_InterestExpenseFederalHomeLoanBankAndFederalReserveBankAdvancesLongTerm_019e41f4-826b-7cb4-b0d3-52889c3fc966" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestExpenseSubordinatedNotesAndDebentures_019e41f4-826b-79e3-938a-6c9e9bb35b78" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestExpenseSubordinatedNotesAndDebentures"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InterestExpenseAbstract_019e41f4-826b-7287-aff5-8fcb5e24be4c" xlink:to="loc_us-gaap_InterestExpenseSubordinatedNotesAndDebentures_019e41f4-826b-79e3-938a-6c9e9bb35b78" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestExpenseOperating_019e41f4-826b-753f-b259-16ed44a428cb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestExpenseOperating"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InterestExpenseAbstract_019e41f4-826b-7287-aff5-8fcb5e24be4c" xlink:to="loc_us-gaap_InterestExpenseOperating_019e41f4-826b-753f-b259-16ed44a428cb" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestIncomeExpenseNet_019e41f4-826b-7798-8203-69380d45f0d5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestIncomeExpenseNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e41f4-826b-7867-9bd7-9064c971a8dc" xlink:to="loc_us-gaap_InterestIncomeExpenseNet_019e41f4-826b-7798-8203-69380d45f0d5" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProvisionForLoanLeaseAndOtherLosses_019e41f4-826b-746f-b5c7-e88589de7338" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProvisionForLoanLeaseAndOtherLosses"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e41f4-826b-7867-9bd7-9064c971a8dc" xlink:to="loc_us-gaap_ProvisionForLoanLeaseAndOtherLosses_019e41f4-826b-746f-b5c7-e88589de7338" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestIncomeExpenseAfterProvisionForLoanLoss_019e41f4-826b-7da0-85c5-f57537621187" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestIncomeExpenseAfterProvisionForLoanLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e41f4-826b-7867-9bd7-9064c971a8dc" xlink:to="loc_us-gaap_InterestIncomeExpenseAfterProvisionForLoanLoss_019e41f4-826b-7da0-85c5-f57537621187" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NoninterestIncomeAbstract_019e41f4-826b-783c-aa7d-0693c0b1c9c0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NoninterestIncomeAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e41f4-826b-7867-9bd7-9064c971a8dc" xlink:to="loc_us-gaap_NoninterestIncomeAbstract_019e41f4-826b-783c-aa7d-0693c0b1c9c0" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_019e41f4-826b-7a2b-bb16-5c8ffb3212d0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NoninterestIncomeAbstract_019e41f4-826b-783c-aa7d-0693c0b1c9c0" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_019e41f4-826b-7a2b-bb16-5c8ffb3212d0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainLossOnSalesOfLoansNet_019e41f4-826b-7065-a1bf-0bd400aa45ba" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_GainLossOnSalesOfLoansNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NoninterestIncomeAbstract_019e41f4-826b-783c-aa7d-0693c0b1c9c0" xlink:to="loc_us-gaap_GainLossOnSalesOfLoansNet_019e41f4-826b-7065-a1bf-0bd400aa45ba" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BankOwnedLifeInsuranceIncome_019e41f4-826b-771d-a254-cec3e8365c4e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BankOwnedLifeInsuranceIncome"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NoninterestIncomeAbstract_019e41f4-826b-783c-aa7d-0693c0b1c9c0" xlink:to="loc_us-gaap_BankOwnedLifeInsuranceIncome_019e41f4-826b-771d-a254-cec3e8365c4e" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleUnrealizedGainLoss_019e41f4-826b-71a8-b9e9-415e10f30bbd" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtSecuritiesAvailableForSaleUnrealizedGainLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NoninterestIncomeAbstract_019e41f4-826b-783c-aa7d-0693c0b1c9c0" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleUnrealizedGainLoss_019e41f4-826b-71a8-b9e9-415e10f30bbd" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_GainLossOnLoanMortgageTransferredToHeldForSale_019e41f4-826b-7639-8b15-84371e1116b2" xlink:href="frme-20260630.xsd#frme_GainLossOnLoanMortgageTransferredToHeldForSale"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NoninterestIncomeAbstract_019e41f4-826b-783c-aa7d-0693c0b1c9c0" xlink:to="loc_frme_GainLossOnLoanMortgageTransferredToHeldForSale_019e41f4-826b-7639-8b15-84371e1116b2" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NoninterestIncomeOtherOperatingIncome_019e41f4-826b-7f42-baf8-d51dd20801e7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NoninterestIncomeOtherOperatingIncome"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NoninterestIncomeAbstract_019e41f4-826b-783c-aa7d-0693c0b1c9c0" xlink:to="loc_us-gaap_NoninterestIncomeOtherOperatingIncome_019e41f4-826b-7f42-baf8-d51dd20801e7" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NoninterestIncome_019e41f4-826b-73ae-b8f0-034d694a34a8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NoninterestIncome"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NoninterestIncomeAbstract_019e41f4-826b-783c-aa7d-0693c0b1c9c0" xlink:to="loc_us-gaap_NoninterestIncome_019e41f4-826b-73ae-b8f0-034d694a34a8" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NoninterestExpenseAbstract_019e41f4-826b-78d2-ab8e-f1c2ac440ded" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NoninterestExpenseAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e41f4-826b-7867-9bd7-9064c971a8dc" xlink:to="loc_us-gaap_NoninterestExpenseAbstract_019e41f4-826b-78d2-ab8e-f1c2ac440ded" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LaborAndRelatedExpense_019e41f4-826b-74d5-9d76-4fa8ce8ff9c9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LaborAndRelatedExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NoninterestExpenseAbstract_019e41f4-826b-78d2-ab8e-f1c2ac440ded" xlink:to="loc_us-gaap_LaborAndRelatedExpense_019e41f4-826b-74d5-9d76-4fa8ce8ff9c9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OccupancyNet_019e41f4-826b-7459-91ea-84248bd433bc" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OccupancyNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NoninterestExpenseAbstract_019e41f4-826b-78d2-ab8e-f1c2ac440ded" xlink:to="loc_us-gaap_OccupancyNet_019e41f4-826b-7459-91ea-84248bd433bc" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquipmentExpense_019e41f4-826b-7531-82cc-c872a6154a66" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquipmentExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NoninterestExpenseAbstract_019e41f4-826b-78d2-ab8e-f1c2ac440ded" xlink:to="loc_us-gaap_EquipmentExpense_019e41f4-826b-7531-82cc-c872a6154a66" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MarketingExpense_019e41f4-826b-75eb-8466-66f8af23f75b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_MarketingExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NoninterestExpenseAbstract_019e41f4-826b-78d2-ab8e-f1c2ac440ded" xlink:to="loc_us-gaap_MarketingExpense_019e41f4-826b-75eb-8466-66f8af23f75b" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InformationTechnologyAndDataProcessing_019e41f4-826b-7c1d-93b0-864942e0ddda" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InformationTechnologyAndDataProcessing"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NoninterestExpenseAbstract_019e41f4-826b-78d2-ab8e-f1c2ac440ded" xlink:to="loc_us-gaap_InformationTechnologyAndDataProcessing_019e41f4-826b-7c1d-93b0-864942e0ddda" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NoninterestExpensePrintingAndFulfillment_019e41f4-826b-79b4-9edd-c701545ad1e1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NoninterestExpensePrintingAndFulfillment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NoninterestExpenseAbstract_019e41f4-826b-78d2-ab8e-f1c2ac440ded" xlink:to="loc_us-gaap_NoninterestExpensePrintingAndFulfillment_019e41f4-826b-79b4-9edd-c701545ad1e1" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AmortizationOfIntangibleAssets_019e41f4-826b-79b6-9a00-cce4b8453d76" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AmortizationOfIntangibleAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NoninterestExpenseAbstract_019e41f4-826b-78d2-ab8e-f1c2ac440ded" xlink:to="loc_us-gaap_AmortizationOfIntangibleAssets_019e41f4-826b-79b6-9a00-cce4b8453d76" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FederalDepositInsuranceCorporationPremiumExpense_019e41f4-826b-7e97-b612-f54dafae78af" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FederalDepositInsuranceCorporationPremiumExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NoninterestExpenseAbstract_019e41f4-826b-78d2-ab8e-f1c2ac440ded" xlink:to="loc_us-gaap_FederalDepositInsuranceCorporationPremiumExpense_019e41f4-826b-7e97-b612-f54dafae78af" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_OtherRealEstateOwnedAndForeclosureExpenses_019e41f4-826b-7192-a25a-1ad0aac7a789" xlink:href="frme-20260630.xsd#frme_OtherRealEstateOwnedAndForeclosureExpenses"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NoninterestExpenseAbstract_019e41f4-826b-78d2-ab8e-f1c2ac440ded" xlink:to="loc_frme_OtherRealEstateOwnedAndForeclosureExpenses_019e41f4-826b-7192-a25a-1ad0aac7a789" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProfessionalAndContractServicesExpense_019e41f4-826b-7275-822a-537f23c83bc6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProfessionalAndContractServicesExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NoninterestExpenseAbstract_019e41f4-826b-78d2-ab8e-f1c2ac440ded" xlink:to="loc_us-gaap_ProfessionalAndContractServicesExpense_019e41f4-826b-7275-822a-537f23c83bc6" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherNoninterestExpense_019e41f4-826b-79a6-a6a2-da0d31b3c465" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherNoninterestExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NoninterestExpenseAbstract_019e41f4-826b-78d2-ab8e-f1c2ac440ded" xlink:to="loc_us-gaap_OtherNoninterestExpense_019e41f4-826b-79a6-a6a2-da0d31b3c465" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NoninterestExpense_019e41f4-826b-786c-b8fa-03f66a3381d0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NoninterestExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NoninterestExpenseAbstract_019e41f4-826b-78d2-ab8e-f1c2ac440ded" xlink:to="loc_us-gaap_NoninterestExpense_019e41f4-826b-786c-b8fa-03f66a3381d0" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_019e41f4-826b-7b3b-9495-1fb8d8e9b8f2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e41f4-826b-7867-9bd7-9064c971a8dc" xlink:to="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_019e41f4-826b-7b3b-9495-1fb8d8e9b8f2" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxExpenseBenefit_019e41f4-826b-7167-8f1b-db77b3f002bd" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeTaxExpenseBenefit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e41f4-826b-7867-9bd7-9064c971a8dc" xlink:to="loc_us-gaap_IncomeTaxExpenseBenefit_019e41f4-826b-7167-8f1b-db77b3f002bd" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_019e41f4-826b-7291-b816-7bfe85e5f1a7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e41f4-826b-7867-9bd7-9064c971a8dc" xlink:to="loc_us-gaap_NetIncomeLoss_019e41f4-826b-7291-b816-7bfe85e5f1a7" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockDividendsIncomeStatementImpact_019e41f4-826b-7dda-9eb4-db171718abb9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PreferredStockDividendsIncomeStatementImpact"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e41f4-826b-7867-9bd7-9064c971a8dc" xlink:to="loc_us-gaap_PreferredStockDividendsIncomeStatementImpact_019e41f4-826b-7dda-9eb4-db171718abb9" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic_019e41f4-826b-7bcf-b5f6-62d51c88574b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e41f4-826b-7867-9bd7-9064c971a8dc" xlink:to="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic_019e41f4-826b-7bcf-b5f6-62d51c88574b" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareAbstract_019e41f4-826b-78f0-a509-a5d2210fa505" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EarningsPerShareAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e41f4-826b-7867-9bd7-9064c971a8dc" xlink:to="loc_us-gaap_EarningsPerShareAbstract_019e41f4-826b-78f0-a509-a5d2210fa505" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareBasic_019e41f4-826b-7fa1-93c0-01134bd921e0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EarningsPerShareBasic"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareAbstract_019e41f4-826b-78f0-a509-a5d2210fa505" xlink:to="loc_us-gaap_EarningsPerShareBasic_019e41f4-826b-7fa1-93c0-01134bd921e0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareDiluted_019e41f4-826b-76f6-9caf-5d6def8f63b9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EarningsPerShareDiluted"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareAbstract_019e41f4-826b-78f0-a509-a5d2210fa505" xlink:to="loc_us-gaap_EarningsPerShareDiluted_019e41f4-826b-76f6-9caf-5d6def8f63b9" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockDividendsPerShareCashPaid_019e41f4-826b-774d-832d-efb1fd35b5d2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockDividendsPerShareCashPaid"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareAbstract_019e41f4-826b-78f0-a509-a5d2210fa505" xlink:to="loc_us-gaap_CommonStockDividendsPerShareCashPaid_019e41f4-826b-774d-832d-efb1fd35b5d2" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_019e41f4-826b-7021-9757-51493a498d72" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareAbstract_019e41f4-826b-78f0-a509-a5d2210fa505" xlink:to="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_019e41f4-826b-7021-9757-51493a498d72" xlink:type="arc" order="4"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.firstmerchants.com/role/CONSOLIDATEDCONDENSEDSTATEMENTSOFSTOCKHOLDERSEQUITYUnaudited" xlink:type="simple" xlink:href="frme-20260630.xsd#CONSOLIDATEDCONDENSEDSTATEMENTSOFSTOCKHOLDERSEQUITYUnaudited"/>
  <link:definitionLink xlink:role="http://www.firstmerchants.com/role/CONSOLIDATEDCONDENSEDSTATEMENTSOFSTOCKHOLDERSEQUITYUnaudited" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_019e41f4-826b-7be1-a340-6c5dd9b13d08" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_019e41f4-826b-765e-8d1f-5f0956248492" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_019e41f4-826b-7be1-a340-6c5dd9b13d08" xlink:to="loc_us-gaap_StatementTable_019e41f4-826b-765e-8d1f-5f0956248492" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_019e41f4-826b-775e-b249-72c1cea130cd" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_019e41f4-826b-765e-8d1f-5f0956248492" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_019e41f4-826b-775e-b249-72c1cea130cd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_019e41f4-826b-775e-b249-72c1cea130cd_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_019e41f4-826b-775e-b249-72c1cea130cd" xlink:to="loc_us-gaap_EquityComponentDomain_019e41f4-826b-775e-b249-72c1cea130cd_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_019e41f4-826b-78d5-9297-d85eb4e0054e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_019e41f4-826b-775e-b249-72c1cea130cd" xlink:to="loc_us-gaap_EquityComponentDomain_019e41f4-826b-78d5-9297-d85eb4e0054e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockMember_019e41f4-826b-7ebc-b232-22068361039e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PreferredStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_019e41f4-826b-78d5-9297-d85eb4e0054e" xlink:to="loc_us-gaap_PreferredStockMember_019e41f4-826b-7ebc-b232-22068361039e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockMember_019e41f4-826b-79a9-bee6-e9dcbbbc5ec6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_019e41f4-826b-78d5-9297-d85eb4e0054e" xlink:to="loc_us-gaap_CommonStockMember_019e41f4-826b-79a9-bee6-e9dcbbbc5ec6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdditionalPaidInCapitalMember_019e41f4-826b-7b79-97b0-193cdf083432" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AdditionalPaidInCapitalMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_019e41f4-826b-78d5-9297-d85eb4e0054e" xlink:to="loc_us-gaap_AdditionalPaidInCapitalMember_019e41f4-826b-7b79-97b0-193cdf083432" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetainedEarningsMember_019e41f4-826b-7bdb-b520-57dd6d64293f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RetainedEarningsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_019e41f4-826b-78d5-9297-d85eb4e0054e" xlink:to="loc_us-gaap_RetainedEarningsMember_019e41f4-826b-7bdb-b520-57dd6d64293f" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_019e41f4-826b-7acd-9476-cbc51db948e5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_019e41f4-826b-78d5-9297-d85eb4e0054e" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_019e41f4-826b-7acd-9476-cbc51db948e5" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementClassOfStockAxis_019e41f4-826b-714d-aaa1-ab7b116e47f6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementClassOfStockAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_019e41f4-826b-765e-8d1f-5f0956248492" xlink:to="loc_us-gaap_StatementClassOfStockAxis_019e41f4-826b-714d-aaa1-ab7b116e47f6" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_019e41f4-826b-714d-aaa1-ab7b116e47f6_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_019e41f4-826b-714d-aaa1-ab7b116e47f6" xlink:to="loc_us-gaap_ClassOfStockDomain_019e41f4-826b-714d-aaa1-ab7b116e47f6_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_019e41f4-826b-701c-9405-2337f7849906" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_019e41f4-826b-714d-aaa1-ab7b116e47f6" xlink:to="loc_us-gaap_ClassOfStockDomain_019e41f4-826b-701c-9405-2337f7849906" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CumulativePreferredStockMember_019e41f4-826b-7e45-b19f-36f04338b02d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CumulativePreferredStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_019e41f4-826b-701c-9405-2337f7849906" xlink:to="loc_us-gaap_CumulativePreferredStockMember_019e41f4-826b-7e45-b19f-36f04338b02d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NoncumulativePreferredStockMember_019e41f4-826b-7131-a2b3-3e30411ed478" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NoncumulativePreferredStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_019e41f4-826b-701c-9405-2337f7849906" xlink:to="loc_us-gaap_NoncumulativePreferredStockMember_019e41f4-826b-7131-a2b3-3e30411ed478" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e41f4-826b-7a8e-b4c3-0e09883e9557" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncreaseDecreaseInStockholdersEquityRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e41f4-826b-7be1-a340-6c5dd9b13d08" xlink:to="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e41f4-826b-7a8e-b4c3-0e09883e9557" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockSharesOutstanding_019e41f4-826b-7296-935c-6f85e20a5d25" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PreferredStockSharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e41f4-826b-7a8e-b4c3-0e09883e9557" xlink:to="loc_us-gaap_PreferredStockSharesOutstanding_019e41f4-826b-7296-935c-6f85e20a5d25" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_019e41f4-826b-7475-8e67-8b2771f2d9b6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockholdersEquity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e41f4-826b-7a8e-b4c3-0e09883e9557" xlink:to="loc_us-gaap_StockholdersEquity_019e41f4-826b-7475-8e67-8b2771f2d9b6" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesOutstanding_019e41f4-826b-7828-bf0b-e3beddacbd5f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockSharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e41f4-826b-7a8e-b4c3-0e09883e9557" xlink:to="loc_us-gaap_CommonStockSharesOutstanding_019e41f4-826b-7828-bf0b-e3beddacbd5f" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ComprehensiveIncomeNetOfTaxAbstract_019e41f4-826b-791a-b472-6de061cd1623" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ComprehensiveIncomeNetOfTaxAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e41f4-826b-7a8e-b4c3-0e09883e9557" xlink:to="loc_us-gaap_ComprehensiveIncomeNetOfTaxAbstract_019e41f4-826b-791a-b472-6de061cd1623" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_019e41f4-826b-7f92-af9e-5b43b0d40213" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ComprehensiveIncomeNetOfTaxAbstract_019e41f4-826b-791a-b472-6de061cd1623" xlink:to="loc_us-gaap_NetIncomeLoss_019e41f4-826b-7f92-af9e-5b43b0d40213" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_019e41f4-826b-7dc3-b2bf-4ba2175be6dc" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ComprehensiveIncomeNetOfTaxAbstract_019e41f4-826b-791a-b472-6de061cd1623" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_019e41f4-826b-7dc3-b2bf-4ba2175be6dc" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DividendsPreferredStockCash_019e41f4-826b-7812-b5b9-65de045911f6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DividendsPreferredStockCash"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e41f4-826b-7a8e-b4c3-0e09883e9557" xlink:to="loc_us-gaap_DividendsPreferredStockCash_019e41f4-826b-7812-b5b9-65de045911f6" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DividendsCommonStockCash_019e41f4-826b-7de4-b1f0-705af6f4b41f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DividendsCommonStockCash"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e41f4-826b-7a8e-b4c3-0e09883e9557" xlink:to="loc_us-gaap_DividendsCommonStockCash_019e41f4-826b-7de4-b1f0-705af6f4b41f" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesAcquisitions_019e41f4-826b-73db-92ec-912db68aa8b9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockIssuedDuringPeriodSharesAcquisitions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e41f4-826b-7a8e-b4c3-0e09883e9557" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesAcquisitions_019e41f4-826b-73db-92ec-912db68aa8b9" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueAcquisitions_019e41f4-826b-7845-865e-68170bfadcb6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockIssuedDuringPeriodValueAcquisitions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e41f4-826b-7a8e-b4c3-0e09883e9557" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueAcquisitions_019e41f4-826b-7845-865e-68170bfadcb6" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockRepurchasedAndRetiredDuringPeriodShares_019e41f4-826b-75d1-910f-2d46939b5cee" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockRepurchasedAndRetiredDuringPeriodShares"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e41f4-826b-7a8e-b4c3-0e09883e9557" xlink:to="loc_us-gaap_StockRepurchasedAndRetiredDuringPeriodShares_019e41f4-826b-75d1-910f-2d46939b5cee" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockRepurchasedAndRetiredDuringPeriodValue_019e41f4-826b-7a46-b278-55dfd0a63055" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockRepurchasedAndRetiredDuringPeriodValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e41f4-826b-7a8e-b4c3-0e09883e9557" xlink:to="loc_us-gaap_StockRepurchasedAndRetiredDuringPeriodValue_019e41f4-826b-7a46-b278-55dfd0a63055" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareRepurchaseProgramExciseTax_019e41f4-826b-7619-8cf6-1f6af5418b6a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareRepurchaseProgramExciseTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e41f4-826b-7a8e-b4c3-0e09883e9557" xlink:to="loc_us-gaap_ShareRepurchaseProgramExciseTax_019e41f4-826b-7619-8cf6-1f6af5418b6a" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation_019e41f4-826b-7139-85c5-51f3d80930bc" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e41f4-826b-7a8e-b4c3-0e09883e9557" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation_019e41f4-826b-7139-85c5-51f3d80930bc" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueShareBasedCompensation_019e41f4-826b-70a0-8f5f-66b781448040" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockIssuedDuringPeriodValueShareBasedCompensation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e41f4-826b-7a8e-b4c3-0e09883e9557" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueShareBasedCompensation_019e41f4-826b-70a0-8f5f-66b781448040" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesEmployeeBenefitPlan_019e41f4-826b-7074-8d19-5a0f1e98e260" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockIssuedDuringPeriodSharesEmployeeBenefitPlan"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e41f4-826b-7a8e-b4c3-0e09883e9557" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesEmployeeBenefitPlan_019e41f4-826b-7074-8d19-5a0f1e98e260" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueEmployeeBenefitPlan_019e41f4-826b-7fdc-bc34-9305037b41f2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockIssuedDuringPeriodValueEmployeeBenefitPlan"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e41f4-826b-7a8e-b4c3-0e09883e9557" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueEmployeeBenefitPlan_019e41f4-826b-7fdc-bc34-9305037b41f2" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_StockIssuedUnderDividendReinvestmentAndStockPurchasePlanInShares_019e41f4-826b-7734-a77e-6e6fbfaf8796" xlink:href="frme-20260630.xsd#frme_StockIssuedUnderDividendReinvestmentAndStockPurchasePlanInShares"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e41f4-826b-7a8e-b4c3-0e09883e9557" xlink:to="loc_frme_StockIssuedUnderDividendReinvestmentAndStockPurchasePlanInShares_019e41f4-826b-7734-a77e-6e6fbfaf8796" xlink:type="arc" order="16"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_StockIssuedUnderDividendReinvestmentAndStockPurchasePlan_019e41f4-826b-7f0a-a883-c641066838bc" xlink:href="frme-20260630.xsd#frme_StockIssuedUnderDividendReinvestmentAndStockPurchasePlan"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e41f4-826b-7a8e-b4c3-0e09883e9557" xlink:to="loc_frme_StockIssuedUnderDividendReinvestmentAndStockPurchasePlan_019e41f4-826b-7f0a-a883-c641066838bc" xlink:type="arc" order="17"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised_019e41f4-826b-7505-b39e-9cc4a6ce2782" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e41f4-826b-7a8e-b4c3-0e09883e9557" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised_019e41f4-826b-7505-b39e-9cc4a6ce2782" xlink:type="arc" order="18"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised_019e41f4-826b-7c2e-a7ef-e7ab9955ec2a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e41f4-826b-7a8e-b4c3-0e09883e9557" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised_019e41f4-826b-7c2e-a7ef-e7ab9955ec2a" xlink:type="arc" order="19"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharesPaidForTaxWithholdingForShareBasedCompensation_019e41f4-826b-7a86-8940-e0aeb746d1bd" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SharesPaidForTaxWithholdingForShareBasedCompensation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e41f4-826b-7a8e-b4c3-0e09883e9557" xlink:to="loc_us-gaap_SharesPaidForTaxWithholdingForShareBasedCompensation_019e41f4-826b-7a86-8940-e0aeb746d1bd" xlink:type="arc" order="20"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsRelatedToTaxWithholdingForShareBasedCompensation_019e41f4-826b-7794-b2a6-5b36466000fe" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AdjustmentsRelatedToTaxWithholdingForShareBasedCompensation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e41f4-826b-7a8e-b4c3-0e09883e9557" xlink:to="loc_us-gaap_AdjustmentsRelatedToTaxWithholdingForShareBasedCompensation_019e41f4-826b-7794-b2a6-5b36466000fe" xlink:type="arc" order="21"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockSharesOutstanding_019e41f4-826b-72f7-96bc-eb3ca35a796f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PreferredStockSharesOutstanding"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_019e41f4-826b-7afa-8aa8-0bafad6ce336" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockholdersEquity"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesOutstanding_019e41f4-826b-7ec1-8e97-c594de3b09da" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockSharesOutstanding"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.firstmerchants.com/role/GENERALDetails" xlink:type="simple" xlink:href="frme-20260630.xsd#GENERALDetails"/>
  <link:definitionLink xlink:role="http://www.firstmerchants.com/role/GENERALDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_019e41f4-826b-71c8-a00c-9b3ed8daa2b1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleTable_019e41f4-826b-701a-b93a-c12c87ca24d8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_019e41f4-826b-71c8-a00c-9b3ed8daa2b1" xlink:to="loc_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleTable_019e41f4-826b-701a-b93a-c12c87ca24d8" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_019e41f4-826b-7330-b05e-93acc257a94d" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_CumulativeEffectPeriodOfAdoptionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleTable_019e41f4-826b-701a-b93a-c12c87ca24d8" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_019e41f4-826b-7330-b05e-93acc257a94d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_019e41f4-826b-7330-b05e-93acc257a94d_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_CumulativeEffectPeriodOfAdoptionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_019e41f4-826b-7330-b05e-93acc257a94d" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_019e41f4-826b-7330-b05e-93acc257a94d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_019e41f4-826b-79a2-a367-51b909732972" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_CumulativeEffectPeriodOfAdoptionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_019e41f4-826b-7330-b05e-93acc257a94d" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_019e41f4-826b-79a2-a367-51b909732972" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember_019e41f4-826b-7b8e-85d4-71b671187833" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_019e41f4-826b-79a2-a367-51b909732972" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember_019e41f4-826b-7b8e-85d4-71b671187833" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesPeriodIncreaseDecrease_019e41f4-826b-7908-8498-cea48e633c75" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableAllowanceForCreditLossesPeriodIncreaseDecrease"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_019e41f4-826b-71c8-a00c-9b3ed8daa2b1" xlink:to="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesPeriodIncreaseDecrease_019e41f4-826b-7908-8498-cea48e633c75" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossLoanPurchased_019e41f4-826b-7dac-ac29-e502623c55ce" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossLoanPurchased"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_019e41f4-826b-71c8-a00c-9b3ed8daa2b1" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossLoanPurchased_019e41f4-826b-7dac-ac29-e502623c55ce" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableAllowanceForCreditLossPurchasedWithCreditDeteriorationIncrease_019e41f4-826b-780b-9aa8-514ca2d9a630" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableAllowanceForCreditLossPurchasedWithCreditDeteriorationIncrease"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_019e41f4-826b-71c8-a00c-9b3ed8daa2b1" xlink:to="loc_us-gaap_FinancingReceivableAllowanceForCreditLossPurchasedWithCreditDeteriorationIncrease_019e41f4-826b-780b-9aa8-514ca2d9a630" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.firstmerchants.com/role/ACQUISITIONSNarrativeDetails" xlink:type="simple" xlink:href="frme-20260630.xsd#ACQUISITIONSNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.firstmerchants.com/role/ACQUISITIONSNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionLineItems_019e41f4-826b-7b33-9409-8ab27eb8f9a8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessAcquisitionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_019e41f4-826b-70bc-8617-25b3f908afe4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019e41f4-826b-7b33-9409-8ab27eb8f9a8" xlink:to="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_019e41f4-826b-70bc-8617-25b3f908afe4" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_LegalEntityAxis_019e41f4-826b-7e58-bfe0-52bf413b14cf" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_LegalEntityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_019e41f4-826b-70bc-8617-25b3f908afe4" xlink:to="loc_dei_LegalEntityAxis_019e41f4-826b-7e58-bfe0-52bf413b14cf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_019e41f4-826b-7e58-bfe0-52bf413b14cf_default" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_019e41f4-826b-7e58-bfe0-52bf413b14cf" xlink:to="loc_dei_EntityDomain_019e41f4-826b-7e58-bfe0-52bf413b14cf_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_019e41f4-826b-78cf-9746-5f903ccb6269" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_019e41f4-826b-7e58-bfe0-52bf413b14cf" xlink:to="loc_dei_EntityDomain_019e41f4-826b-78cf-9746-5f903ccb6269" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_FirstSavingsFinancialGroupInc.Member_019e41f4-826b-76f3-b4b0-b4fa678e1912" xlink:href="frme-20260630.xsd#frme_FirstSavingsFinancialGroupInc.Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_019e41f4-826b-78cf-9746-5f903ccb6269" xlink:to="loc_frme_FirstSavingsFinancialGroupInc.Member_019e41f4-826b-76f3-b4b0-b4fa678e1912" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_019e41f4-826b-7a3b-9fe1-f63dc3f4d47b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessAcquisitionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_019e41f4-826b-70bc-8617-25b3f908afe4" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_019e41f4-826b-7a3b-9fe1-f63dc3f4d47b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_019e41f4-826b-7a3b-9fe1-f63dc3f4d47b_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_019e41f4-826b-7a3b-9fe1-f63dc3f4d47b" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_019e41f4-826b-7a3b-9fe1-f63dc3f4d47b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_019e41f4-826b-761e-b343-fe7a4d182a56" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_019e41f4-826b-7a3b-9fe1-f63dc3f4d47b" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_019e41f4-826b-761e-b343-fe7a4d182a56" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_FirstSavingsFinancialGroupInc.Member_019e41f4-826b-760e-a6e2-a8624726ca79" xlink:href="frme-20260630.xsd#frme_FirstSavingsFinancialGroupInc.Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_019e41f4-826b-761e-b343-fe7a4d182a56" xlink:to="loc_frme_FirstSavingsFinancialGroupInc.Member_019e41f4-826b-760e-a6e2-a8624726ca79" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementClassOfStockAxis_019e41f4-826b-7a8e-bc5f-ebe7c49cf704" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementClassOfStockAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_019e41f4-826b-70bc-8617-25b3f908afe4" xlink:to="loc_us-gaap_StatementClassOfStockAxis_019e41f4-826b-7a8e-bc5f-ebe7c49cf704" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_019e41f4-826b-7a8e-bc5f-ebe7c49cf704_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_019e41f4-826b-7a8e-bc5f-ebe7c49cf704" xlink:to="loc_us-gaap_ClassOfStockDomain_019e41f4-826b-7a8e-bc5f-ebe7c49cf704_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_019e41f4-826b-737d-9544-4f8484afbae8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_019e41f4-826b-7a8e-bc5f-ebe7c49cf704" xlink:to="loc_us-gaap_ClassOfStockDomain_019e41f4-826b-737d-9544-4f8484afbae8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockMember_019e41f4-826b-743c-8b08-fbe7fbf22cb0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_019e41f4-826b-737d-9544-4f8484afbae8" xlink:to="loc_us-gaap_CommonStockMember_019e41f4-826b-743c-8b08-fbe7fbf22cb0" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_019e41f4-826b-7f3d-9d2a-869a919e2ee5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_019e41f4-826b-70bc-8617-25b3f908afe4" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_019e41f4-826b-7f3d-9d2a-869a919e2ee5" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_019e41f4-826b-7f3d-9d2a-869a919e2ee5_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_019e41f4-826b-7f3d-9d2a-869a919e2ee5" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_019e41f4-826b-7f3d-9d2a-869a919e2ee5_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_019e41f4-826b-70d0-a2d6-64fffd589904" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_019e41f4-826b-7f3d-9d2a-869a919e2ee5" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_019e41f4-826b-70d0-a2d6-64fffd589904" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CoreDepositsMember_019e41f4-826b-730d-9855-11da11fe25e2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CoreDepositsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_019e41f4-826b-70d0-a2d6-64fffd589904" xlink:to="loc_us-gaap_CoreDepositsMember_019e41f4-826b-730d-9855-11da11fe25e2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherIntangibleAssetsMember_019e41f4-826b-7fa3-afa9-b621b4352cc7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherIntangibleAssetsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_019e41f4-826b-70d0-a2d6-64fffd589904" xlink:to="loc_us-gaap_OtherIntangibleAssetsMember_019e41f4-826b-7fa3-afa9-b621b4352cc7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementOfIncomeLocationBalanceAxis_019e41f4-826b-725d-a1c3-1b438206b00b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementOfIncomeLocationBalanceAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_019e41f4-826b-70bc-8617-25b3f908afe4" xlink:to="loc_us-gaap_StatementOfIncomeLocationBalanceAxis_019e41f4-826b-725d-a1c3-1b438206b00b" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_NumberOfBankingCenters_019e41f4-826b-7b18-877f-0872f4f89445" xlink:href="frme-20260630.xsd#frme_NumberOfBankingCenters"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019e41f4-826b-7b33-9409-8ab27eb8f9a8" xlink:to="loc_frme_NumberOfBankingCenters_019e41f4-826b-7b18-877f-0872f4f89445" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_BusinessCombinationExchangeRatio_019e41f4-826b-7153-ac7f-23663022a985" xlink:href="frme-20260630.xsd#frme_BusinessCombinationExchangeRatio"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019e41f4-826b-7b33-9409-8ab27eb8f9a8" xlink:to="loc_frme_BusinessCombinationExchangeRatio_019e41f4-826b-7153-ac7f-23663022a985" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionSharePrice_019e41f4-826b-792a-8774-f449e09f6da7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessAcquisitionSharePrice"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019e41f4-826b-7b33-9409-8ab27eb8f9a8" xlink:to="loc_us-gaap_BusinessAcquisitionSharePrice_019e41f4-826b-792a-8774-f449e09f6da7" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_BusinessCombinationNumberOfConsecutiveTradingDays_019e41f4-826b-7a14-ac39-47a6520754a0" xlink:href="frme-20260630.xsd#frme_BusinessCombinationNumberOfConsecutiveTradingDays"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019e41f4-826b-7b33-9409-8ab27eb8f9a8" xlink:to="loc_frme_BusinessCombinationNumberOfConsecutiveTradingDays_019e41f4-826b-7a14-ac39-47a6520754a0" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionEquityInterestsIssuedOrIssuableNumberOfSharesIssued_019e41f4-826b-7577-a519-aed609c7e8b4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessAcquisitionEquityInterestsIssuedOrIssuableNumberOfSharesIssued"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019e41f4-826b-7b33-9409-8ab27eb8f9a8" xlink:to="loc_us-gaap_BusinessAcquisitionEquityInterestsIssuedOrIssuableNumberOfSharesIssued_019e41f4-826b-7577-a519-aed609c7e8b4" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationConsiderationTransferred1_019e41f4-826b-72f7-aef0-4aa3c795d777" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessCombinationConsiderationTransferred1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019e41f4-826b-7b33-9409-8ab27eb8f9a8" xlink:to="loc_us-gaap_BusinessCombinationConsiderationTransferred1_019e41f4-826b-72f7-aef0-4aa3c795d777" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinitelivedIntangibleAssetsAcquired1_019e41f4-826b-725e-a13f-9e60bdea0109" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinitelivedIntangibleAssetsAcquired1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019e41f4-826b-7b33-9409-8ab27eb8f9a8" xlink:to="loc_us-gaap_FinitelivedIntangibleAssetsAcquired1_019e41f4-826b-725e-a13f-9e60bdea0109" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetUsefulLife_019e41f4-826b-736b-8394-41c2dded313c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FiniteLivedIntangibleAssetUsefulLife"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019e41f4-826b-7b33-9409-8ab27eb8f9a8" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetUsefulLife_019e41f4-826b-736b-8394-41c2dded313c" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationAcquisitionRelatedCosts_019e41f4-826b-770f-ac3e-ee9037a8f348" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessCombinationAcquisitionRelatedCosts"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019e41f4-826b-7b33-9409-8ab27eb8f9a8" xlink:to="loc_us-gaap_BusinessCombinationAcquisitionRelatedCosts_019e41f4-826b-770f-ac3e-ee9037a8f348" xlink:type="arc" order="8"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.firstmerchants.com/role/ACQUISITIONSNarrativeDetails_1" xlink:type="simple" xlink:href="frme-20260630.xsd#ACQUISITIONSNarrativeDetails_1"/>
  <link:definitionLink xlink:role="http://www.firstmerchants.com/role/ACQUISITIONSNarrativeDetails_1" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionLineItems_019e41f4-826b-7b33-9409-8ab27eb8f9a8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessAcquisitionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_019e41f4-826b-70bc-8617-25b3f908afe4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019e41f4-826b-7b33-9409-8ab27eb8f9a8" xlink:to="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_019e41f4-826b-70bc-8617-25b3f908afe4" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_LegalEntityAxis_019e41f4-826b-7e58-bfe0-52bf413b14cf" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_LegalEntityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_019e41f4-826b-70bc-8617-25b3f908afe4" xlink:to="loc_dei_LegalEntityAxis_019e41f4-826b-7e58-bfe0-52bf413b14cf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_019e41f4-826b-7e58-bfe0-52bf413b14cf_default" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_019e41f4-826b-7e58-bfe0-52bf413b14cf" xlink:to="loc_dei_EntityDomain_019e41f4-826b-7e58-bfe0-52bf413b14cf_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_019e41f4-826b-78cf-9746-5f903ccb6269" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_019e41f4-826b-7e58-bfe0-52bf413b14cf" xlink:to="loc_dei_EntityDomain_019e41f4-826b-78cf-9746-5f903ccb6269" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_FirstSavingsFinancialGroupInc.Member_019e41f4-826b-76f3-b4b0-b4fa678e1912" xlink:href="frme-20260630.xsd#frme_FirstSavingsFinancialGroupInc.Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_019e41f4-826b-78cf-9746-5f903ccb6269" xlink:to="loc_frme_FirstSavingsFinancialGroupInc.Member_019e41f4-826b-76f3-b4b0-b4fa678e1912" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_019e41f4-826b-7a3b-9fe1-f63dc3f4d47b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessAcquisitionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_019e41f4-826b-70bc-8617-25b3f908afe4" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_019e41f4-826b-7a3b-9fe1-f63dc3f4d47b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_019e41f4-826b-7a3b-9fe1-f63dc3f4d47b_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_019e41f4-826b-7a3b-9fe1-f63dc3f4d47b" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_019e41f4-826b-7a3b-9fe1-f63dc3f4d47b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_019e41f4-826b-761e-b343-fe7a4d182a56" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_019e41f4-826b-7a3b-9fe1-f63dc3f4d47b" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_019e41f4-826b-761e-b343-fe7a4d182a56" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_FirstSavingsFinancialGroupInc.Member_019e41f4-826b-760e-a6e2-a8624726ca79" xlink:href="frme-20260630.xsd#frme_FirstSavingsFinancialGroupInc.Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_019e41f4-826b-761e-b343-fe7a4d182a56" xlink:to="loc_frme_FirstSavingsFinancialGroupInc.Member_019e41f4-826b-760e-a6e2-a8624726ca79" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementClassOfStockAxis_019e41f4-826b-7a8e-bc5f-ebe7c49cf704" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementClassOfStockAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_019e41f4-826b-70bc-8617-25b3f908afe4" xlink:to="loc_us-gaap_StatementClassOfStockAxis_019e41f4-826b-7a8e-bc5f-ebe7c49cf704" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_019e41f4-826b-7a8e-bc5f-ebe7c49cf704_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_019e41f4-826b-7a8e-bc5f-ebe7c49cf704" xlink:to="loc_us-gaap_ClassOfStockDomain_019e41f4-826b-7a8e-bc5f-ebe7c49cf704_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_019e41f4-826b-737d-9544-4f8484afbae8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_019e41f4-826b-7a8e-bc5f-ebe7c49cf704" xlink:to="loc_us-gaap_ClassOfStockDomain_019e41f4-826b-737d-9544-4f8484afbae8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockMember_019e41f4-826b-743c-8b08-fbe7fbf22cb0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_019e41f4-826b-737d-9544-4f8484afbae8" xlink:to="loc_us-gaap_CommonStockMember_019e41f4-826b-743c-8b08-fbe7fbf22cb0" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_019e41f4-826b-7f3d-9d2a-869a919e2ee5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_019e41f4-826b-70bc-8617-25b3f908afe4" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_019e41f4-826b-7f3d-9d2a-869a919e2ee5" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_019e41f4-826b-7f3d-9d2a-869a919e2ee5_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_019e41f4-826b-7f3d-9d2a-869a919e2ee5" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_019e41f4-826b-7f3d-9d2a-869a919e2ee5_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_019e41f4-826b-70d0-a2d6-64fffd589904" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_019e41f4-826b-7f3d-9d2a-869a919e2ee5" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_019e41f4-826b-70d0-a2d6-64fffd589904" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CoreDepositsMember_019e41f4-826b-730d-9855-11da11fe25e2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CoreDepositsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_019e41f4-826b-70d0-a2d6-64fffd589904" xlink:to="loc_us-gaap_CoreDepositsMember_019e41f4-826b-730d-9855-11da11fe25e2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherIntangibleAssetsMember_019e41f4-826b-7fa3-afa9-b621b4352cc7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherIntangibleAssetsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_019e41f4-826b-70d0-a2d6-64fffd589904" xlink:to="loc_us-gaap_OtherIntangibleAssetsMember_019e41f4-826b-7fa3-afa9-b621b4352cc7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_NumberOfBankingCenters_019e41f4-826b-7b18-877f-0872f4f89445" xlink:href="frme-20260630.xsd#frme_NumberOfBankingCenters"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019e41f4-826b-7b33-9409-8ab27eb8f9a8" xlink:to="loc_frme_NumberOfBankingCenters_019e41f4-826b-7b18-877f-0872f4f89445" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_BusinessCombinationExchangeRatio_019e41f4-826b-7153-ac7f-23663022a985" xlink:href="frme-20260630.xsd#frme_BusinessCombinationExchangeRatio"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019e41f4-826b-7b33-9409-8ab27eb8f9a8" xlink:to="loc_frme_BusinessCombinationExchangeRatio_019e41f4-826b-7153-ac7f-23663022a985" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionSharePrice_019e41f4-826b-792a-8774-f449e09f6da7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessAcquisitionSharePrice"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019e41f4-826b-7b33-9409-8ab27eb8f9a8" xlink:to="loc_us-gaap_BusinessAcquisitionSharePrice_019e41f4-826b-792a-8774-f449e09f6da7" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_BusinessCombinationNumberOfConsecutiveTradingDays_019e41f4-826b-7a14-ac39-47a6520754a0" xlink:href="frme-20260630.xsd#frme_BusinessCombinationNumberOfConsecutiveTradingDays"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019e41f4-826b-7b33-9409-8ab27eb8f9a8" xlink:to="loc_frme_BusinessCombinationNumberOfConsecutiveTradingDays_019e41f4-826b-7a14-ac39-47a6520754a0" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionEquityInterestsIssuedOrIssuableNumberOfSharesIssued_019e41f4-826b-7577-a519-aed609c7e8b4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessAcquisitionEquityInterestsIssuedOrIssuableNumberOfSharesIssued"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019e41f4-826b-7b33-9409-8ab27eb8f9a8" xlink:to="loc_us-gaap_BusinessAcquisitionEquityInterestsIssuedOrIssuableNumberOfSharesIssued_019e41f4-826b-7577-a519-aed609c7e8b4" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationConsiderationTransferred1_019e41f4-826b-72f7-aef0-4aa3c795d777" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessCombinationConsiderationTransferred1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019e41f4-826b-7b33-9409-8ab27eb8f9a8" xlink:to="loc_us-gaap_BusinessCombinationConsiderationTransferred1_019e41f4-826b-72f7-aef0-4aa3c795d777" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinitelivedIntangibleAssetsAcquired1_019e41f4-826b-725e-a13f-9e60bdea0109" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinitelivedIntangibleAssetsAcquired1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019e41f4-826b-7b33-9409-8ab27eb8f9a8" xlink:to="loc_us-gaap_FinitelivedIntangibleAssetsAcquired1_019e41f4-826b-725e-a13f-9e60bdea0109" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetUsefulLife_019e41f4-826b-736b-8394-41c2dded313c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FiniteLivedIntangibleAssetUsefulLife"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019e41f4-826b-7b33-9409-8ab27eb8f9a8" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetUsefulLife_019e41f4-826b-736b-8394-41c2dded313c" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationAcquisitionRelatedCosts_019e41f4-826b-770f-ac3e-ee9037a8f348" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessCombinationAcquisitionRelatedCosts"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019e41f4-826b-7b33-9409-8ab27eb8f9a8" xlink:to="loc_us-gaap_BusinessCombinationAcquisitionRelatedCosts_019e41f4-826b-770f-ac3e-ee9037a8f348" xlink:type="arc" order="8"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.firstmerchants.com/role/ACQUISITIONSAssetsAcquiredandLiabilitiesAssumedDetails" xlink:type="simple" xlink:href="frme-20260630.xsd#ACQUISITIONSAssetsAcquiredandLiabilitiesAssumedDetails"/>
  <link:definitionLink xlink:role="http://www.firstmerchants.com/role/ACQUISITIONSAssetsAcquiredandLiabilitiesAssumedDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionLineItems_019e41f4-826b-7da0-a6ef-a11045aa653c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessAcquisitionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_019e41f4-826b-7491-8f56-368f11814c40" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019e41f4-826b-7da0-a6ef-a11045aa653c" xlink:to="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_019e41f4-826b-7491-8f56-368f11814c40" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_019e41f4-826b-7d20-94ca-54caaf525671" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessAcquisitionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_019e41f4-826b-7491-8f56-368f11814c40" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_019e41f4-826b-7d20-94ca-54caaf525671" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_019e41f4-826b-7d20-94ca-54caaf525671_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_019e41f4-826b-7d20-94ca-54caaf525671" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_019e41f4-826b-7d20-94ca-54caaf525671_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_019e41f4-826b-7b4f-8881-c4f783e27f8b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_019e41f4-826b-7d20-94ca-54caaf525671" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_019e41f4-826b-7b4f-8881-c4f783e27f8b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_FirstSavingsFinancialGroupInc.Member_019e41f4-826b-71f7-9c8a-d033f6de746d" xlink:href="frme-20260630.xsd#frme_FirstSavingsFinancialGroupInc.Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_019e41f4-826b-7b4f-8881-c4f783e27f8b" xlink:to="loc_frme_FirstSavingsFinancialGroupInc.Member_019e41f4-826b-71f7-9c8a-d033f6de746d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCashAndEquivalents_019e41f4-826b-7d73-bbf4-98d2d5e25e31" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCashAndEquivalents"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019e41f4-826b-7da0-a6ef-a11045aa653c" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCashAndEquivalents_019e41f4-826b-7d73-bbf4-98d2d5e25e31" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedInterestBearingDeposits_019fb5ce-4d97-71b0-a78e-412e179b8e9e" xlink:href="frme-20260630.xsd#frme_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedInterestBearingDeposits"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019e41f4-826b-7da0-a6ef-a11045aa653c" xlink:to="loc_frme_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedInterestBearingDeposits_019fb5ce-4d97-71b0-a78e-412e179b8e9e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsMarketableSecurities_019e41f4-826b-7da0-9354-8931a302d1d3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsMarketableSecurities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019e41f4-826b-7da0-a6ef-a11045aa653c" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsMarketableSecurities_019e41f4-826b-7da0-9354-8931a302d1d3" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLoansHeldForSale_019e41f4-826b-7077-ac2e-5034bb77a59c" xlink:href="frme-20260630.xsd#frme_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLoansHeldForSale"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019e41f4-826b-7da0-a6ef-a11045aa653c" xlink:to="loc_frme_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLoansHeldForSale_019e41f4-826b-7077-ac2e-5034bb77a59c" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLoans_019e41f4-826b-7152-8222-3c50719e6eb6" xlink:href="frme-20260630.xsd#frme_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLoans"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019e41f4-826b-7da0-a6ef-a11045aa653c" xlink:to="loc_frme_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLoans_019e41f4-826b-7152-8222-3c50719e6eb6" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAllowanceForCreditLossesLoans_019e41f4-826b-796f-8539-b05e4fd016b4" xlink:href="frme-20260630.xsd#frme_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAllowanceForCreditLossesLoans"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019e41f4-826b-7da0-a6ef-a11045aa653c" xlink:to="loc_frme_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAllowanceForCreditLossesLoans_019e41f4-826b-796f-8539-b05e4fd016b4" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment_019e41f4-826b-773d-906e-55afcc99e12c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019e41f4-826b-7da0-a6ef-a11045aa653c" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment_019e41f4-826b-773d-906e-55afcc99e12c" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedFederalHomeLoanBankStock_019e41f4-826b-78b1-bb27-2edfd3d81441" xlink:href="frme-20260630.xsd#frme_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedFederalHomeLoanBankStock"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019e41f4-826b-7da0-a6ef-a11045aa653c" xlink:to="loc_frme_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedFederalHomeLoanBankStock_019e41f4-826b-78b1-bb27-2edfd3d81441" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedOtherRealEstateOwned_019e41f4-826b-7e95-99d8-81b6aae85c48" xlink:href="frme-20260630.xsd#frme_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedOtherRealEstateOwned"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019e41f4-826b-7da0-a6ef-a11045aa653c" xlink:to="loc_frme_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedOtherRealEstateOwned_019e41f4-826b-7e95-99d8-81b6aae85c48" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedInterestReceivable_019e41f4-826b-7a08-ae69-ac6fbd598065" xlink:href="frme-20260630.xsd#frme_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedInterestReceivable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019e41f4-826b-7da0-a6ef-a11045aa653c" xlink:to="loc_frme_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedInterestReceivable_019e41f4-826b-7a08-ae69-ac6fbd598065" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCashSurrenderValueOfLifeInsurance_019e41f4-826b-7c95-a5b5-c1fc18086795" xlink:href="frme-20260630.xsd#frme_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCashSurrenderValueOfLifeInsurance"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019e41f4-826b-7da0-a6ef-a11045aa653c" xlink:to="loc_frme_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCashSurrenderValueOfLifeInsurance_019e41f4-826b-7c95-a5b5-c1fc18086795" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedDeferredTaxAssets_019e41f4-826b-7b1f-9f29-a627241d061a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedDeferredTaxAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019e41f4-826b-7da0-a6ef-a11045aa653c" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedDeferredTaxAssets_019e41f4-826b-7b1f-9f29-a627241d061a" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedOtherNoncurrentAssets_019e41f4-826b-721d-a1b0-dcda520a16d7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedOtherNoncurrentAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019e41f4-826b-7da0-a6ef-a11045aa653c" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedOtherNoncurrentAssets_019e41f4-826b-721d-a1b0-dcda520a16d7" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilitiesAssumedDeposits_019e41f4-826b-77c7-8a53-8302c45721a2" xlink:href="frme-20260630.xsd#frme_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilitiesAssumedDeposits"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019e41f4-826b-7da0-a6ef-a11045aa653c" xlink:to="loc_frme_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilitiesAssumedDeposits_019e41f4-826b-77c7-8a53-8302c45721a2" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilitiesFederalHomeLoanBankAdvances_019e41f4-826b-78ec-b84c-7f54966a6708" xlink:href="frme-20260630.xsd#frme_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilitiesFederalHomeLoanBankAdvances"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019e41f4-826b-7da0-a6ef-a11045aa653c" xlink:to="loc_frme_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilitiesFederalHomeLoanBankAdvances_019e41f4-826b-78ec-b84c-7f54966a6708" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedSubordinatedDebentures_019e41f4-826b-7592-997f-0e07858daa9b" xlink:href="frme-20260630.xsd#frme_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedSubordinatedDebentures"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019e41f4-826b-7da0-a6ef-a11045aa653c" xlink:to="loc_frme_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedSubordinatedDebentures_019e41f4-826b-7592-997f-0e07858daa9b" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilitiesInterestPayable_019e41f4-826b-7807-a296-19be28bd9e04" xlink:href="frme-20260630.xsd#frme_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilitiesInterestPayable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019e41f4-826b-7da0-a6ef-a11045aa653c" xlink:to="loc_frme_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilitiesInterestPayable_019e41f4-826b-7807-a296-19be28bd9e04" xlink:type="arc" order="16"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilitiesOther_019e41f4-826b-7f50-803d-32b0fc8f6086" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilitiesOther"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019e41f4-826b-7da0-a6ef-a11045aa653c" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilitiesOther_019e41f4-826b-7f50-803d-32b0fc8f6086" xlink:type="arc" order="17"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedTangibleAssetsNet_019e41f4-826b-75b3-97cb-1ec6edcd05d1" xlink:href="frme-20260630.xsd#frme_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedTangibleAssetsNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019e41f4-826b-7da0-a6ef-a11045aa653c" xlink:to="loc_frme_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedTangibleAssetsNet_019e41f4-826b-75b3-97cb-1ec6edcd05d1" xlink:type="arc" order="18"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibles_019e41f4-826b-7e10-8e60-0fdb0bc19987" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibles"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019e41f4-826b-7da0-a6ef-a11045aa653c" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibles_019e41f4-826b-7e10-8e60-0fdb0bc19987" xlink:type="arc" order="19"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Goodwill_019e41f4-826b-7f46-bed0-0c436716f242" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_Goodwill"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019e41f4-826b-7da0-a6ef-a11045aa653c" xlink:to="loc_us-gaap_Goodwill_019e41f4-826b-7f46-bed0-0c436716f242" xlink:type="arc" order="20"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNet_019e41f4-826b-791e-b459-a6985d3d65ca" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019e41f4-826b-7da0-a6ef-a11045aa653c" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNet_019e41f4-826b-791e-b459-a6985d3d65ca" xlink:type="arc" order="21"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.firstmerchants.com/role/ACQUISITIONSProFormaFinancialInformationDetails" xlink:type="simple" xlink:href="frme-20260630.xsd#ACQUISITIONSProFormaFinancialInformationDetails"/>
  <link:definitionLink xlink:role="http://www.firstmerchants.com/role/ACQUISITIONSProFormaFinancialInformationDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionLineItems_019e41f4-826b-766b-884e-c154e1470e7c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessAcquisitionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_019e41f4-826b-7ef7-a858-a7a97f403c53" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019e41f4-826b-766b-884e-c154e1470e7c" xlink:to="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_019e41f4-826b-7ef7-a858-a7a97f403c53" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_019e41f4-826b-7b17-92cd-7f5e2625fd55" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessAcquisitionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_019e41f4-826b-7ef7-a858-a7a97f403c53" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_019e41f4-826b-7b17-92cd-7f5e2625fd55" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_019e41f4-826b-7b17-92cd-7f5e2625fd55_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_019e41f4-826b-7b17-92cd-7f5e2625fd55" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_019e41f4-826b-7b17-92cd-7f5e2625fd55_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_019e41f4-826b-7b81-b3f3-f15ac015cbb5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_019e41f4-826b-7b17-92cd-7f5e2625fd55" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_019e41f4-826b-7b81-b3f3-f15ac015cbb5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_FirstSavingsFinancialGroupInc.Member_019e41f4-826b-7742-8a9c-b811121598ed" xlink:href="frme-20260630.xsd#frme_FirstSavingsFinancialGroupInc.Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_019e41f4-826b-7b81-b3f3-f15ac015cbb5" xlink:to="loc_frme_FirstSavingsFinancialGroupInc.Member_019e41f4-826b-7742-8a9c-b811121598ed" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionsProFormaRevenue_019e41f4-826b-716e-a781-19bb10410831" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessAcquisitionsProFormaRevenue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019e41f4-826b-766b-884e-c154e1470e7c" xlink:to="loc_us-gaap_BusinessAcquisitionsProFormaRevenue_019e41f4-826b-716e-a781-19bb10410831" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionsProFormaNetIncomeLoss_019e41f4-826b-73db-b540-ad5a6775ea2d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessAcquisitionsProFormaNetIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019e41f4-826b-766b-884e-c154e1470e7c" xlink:to="loc_us-gaap_BusinessAcquisitionsProFormaNetIncomeLoss_019e41f4-826b-73db-b540-ad5a6775ea2d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_BusinessAcquisitionProFormaNetIncomeLossAvailableToCommonStockholders_019e41f4-826b-7bff-94e3-6b1160502bc8" xlink:href="frme-20260630.xsd#frme_BusinessAcquisitionProFormaNetIncomeLossAvailableToCommonStockholders"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019e41f4-826b-766b-884e-c154e1470e7c" xlink:to="loc_frme_BusinessAcquisitionProFormaNetIncomeLossAvailableToCommonStockholders_019e41f4-826b-7bff-94e3-6b1160502bc8" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareProFormaAbstract_019e41f4-826b-75a8-90bc-845525c9c8cc" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EarningsPerShareProFormaAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019e41f4-826b-766b-884e-c154e1470e7c" xlink:to="loc_us-gaap_EarningsPerShareProFormaAbstract_019e41f4-826b-75a8-90bc-845525c9c8cc" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionProFormaEarningsPerShareBasic_019e41f4-826b-7425-b47e-2b8a72c96e2d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessAcquisitionProFormaEarningsPerShareBasic"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareProFormaAbstract_019e41f4-826b-75a8-90bc-845525c9c8cc" xlink:to="loc_us-gaap_BusinessAcquisitionProFormaEarningsPerShareBasic_019e41f4-826b-7425-b47e-2b8a72c96e2d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionProFormaEarningsPerShareDiluted_019e41f4-826b-73f1-91fd-7b7d1ed2880f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessAcquisitionProFormaEarningsPerShareDiluted"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareProFormaAbstract_019e41f4-826b-75a8-90bc-845525c9c8cc" xlink:to="loc_us-gaap_BusinessAcquisitionProFormaEarningsPerShareDiluted_019e41f4-826b-73f1-91fd-7b7d1ed2880f" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.firstmerchants.com/role/INVESTMENTSECURITIESSummaryofAmortizedCostGrossUnrealizedGainsandLossesandApproximateFairValueofInvestmentSecuritiesDetails" xlink:type="simple" xlink:href="frme-20260630.xsd#INVESTMENTSECURITIESSummaryofAmortizedCostGrossUnrealizedGainsandLossesandApproximateFairValueofInvestmentSecuritiesDetails"/>
  <link:definitionLink xlink:role="http://www.firstmerchants.com/role/INVESTMENTSECURITIESSummaryofAmortizedCostGrossUnrealizedGainsandLossesandApproximateFairValueofInvestmentSecuritiesDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfGainLossOnInvestmentsIncludingMarketableSecuritiesAndInvestmentsHeldAtCostIncomeStatementReportedAmountsSummaryLineItems_019e41f4-826b-7921-b808-6f02236e86c9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfGainLossOnInvestmentsIncludingMarketableSecuritiesAndInvestmentsHeldAtCostIncomeStatementReportedAmountsSummaryLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfGainLossOnInvestmentsTable_019e41f4-826b-740e-9f48-b567f997ed83" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfGainLossOnInvestmentsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ScheduleOfGainLossOnInvestmentsIncludingMarketableSecuritiesAndInvestmentsHeldAtCostIncomeStatementReportedAmountsSummaryLineItems_019e41f4-826b-7921-b808-6f02236e86c9" xlink:to="loc_us-gaap_ScheduleOfGainLossOnInvestmentsTable_019e41f4-826b-740e-9f48-b567f997ed83" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentAxis_019e41f4-826b-797d-b23d-e35b39bdc2b9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancialInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfGainLossOnInvestmentsTable_019e41f4-826b-740e-9f48-b567f997ed83" xlink:to="loc_us-gaap_FinancialInstrumentAxis_019e41f4-826b-797d-b23d-e35b39bdc2b9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e41f4-826b-797d-b23d-e35b39bdc2b9_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentAxis_019e41f4-826b-797d-b23d-e35b39bdc2b9" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e41f4-826b-797d-b23d-e35b39bdc2b9_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e41f4-826b-7a6a-8a71-92262817ae65" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentAxis_019e41f4-826b-797d-b23d-e35b39bdc2b9" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e41f4-826b-7a6a-8a71-92262817ae65" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_USGovernmentAgenciesDebtSecuritiesMember_019e41f4-826b-7b4f-ae74-55a23247eff6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_USGovernmentAgenciesDebtSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e41f4-826b-7a6a-8a71-92262817ae65" xlink:to="loc_us-gaap_USGovernmentAgenciesDebtSecuritiesMember_019e41f4-826b-7b4f-ae74-55a23247eff6" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_USStatesAndPoliticalSubdivisionsMember_019e41f4-826b-7e07-9e48-cfedfdf546c5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_USStatesAndPoliticalSubdivisionsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e41f4-826b-7a6a-8a71-92262817ae65" xlink:to="loc_us-gaap_USStatesAndPoliticalSubdivisionsMember_019e41f4-826b-7e07-9e48-cfedfdf546c5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember_019e41f4-826b-7789-a53b-351b24921c6c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e41f4-826b-7a6a-8a71-92262817ae65" xlink:to="loc_us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember_019e41f4-826b-7789-a53b-351b24921c6c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ForeignGovernmentDebtSecuritiesMember_019e41f4-826b-7476-883c-c634c0b520d6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ForeignGovernmentDebtSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e41f4-826b-7a6a-8a71-92262817ae65" xlink:to="loc_us-gaap_ForeignGovernmentDebtSecuritiesMember_019e41f4-826b-7476-883c-c634c0b520d6" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CorporateDebtSecuritiesMember_019e41f4-826b-7000-9be0-87ff26553208" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CorporateDebtSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e41f4-826b-7a6a-8a71-92262817ae65" xlink:to="loc_us-gaap_CorporateDebtSecuritiesMember_019e41f4-826b-7000-9be0-87ff26553208" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesAbstract_019e41f4-826b-7e5e-88ac-16fed589ee6d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AvailableForSaleSecuritiesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfGainLossOnInvestmentsIncludingMarketableSecuritiesAndInvestmentsHeldAtCostIncomeStatementReportedAmountsSummaryLineItems_019e41f4-826b-7921-b808-6f02236e86c9" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesAbstract_019e41f4-826b-7e5e-88ac-16fed589ee6d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleAmortizedCostExcludingAccruedInterestBeforeAllowanceForCreditLoss_019e41f4-826b-770a-8973-c89d6e77bfb5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtSecuritiesAvailableForSaleAmortizedCostExcludingAccruedInterestBeforeAllowanceForCreditLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesAbstract_019e41f4-826b-7e5e-88ac-16fed589ee6d" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleAmortizedCostExcludingAccruedInterestBeforeAllowanceForCreditLoss_019e41f4-826b-770a-8973-c89d6e77bfb5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax_019e41f4-826b-71a2-a6ae-6185ed28c273" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesAbstract_019e41f4-826b-7e5e-88ac-16fed589ee6d" xlink:to="loc_us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax_019e41f4-826b-71a2-a6ae-6185ed28c273" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax_019e41f4-826b-7507-b3e0-7bdb7901bd0e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesAbstract_019e41f4-826b-7e5e-88ac-16fed589ee6d" xlink:to="loc_us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax_019e41f4-826b-7507-b3e0-7bdb7901bd0e" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleExcludingAccruedInterest_019e41f4-826b-77a1-b64b-84a69a950594" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtSecuritiesAvailableForSaleExcludingAccruedInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesAbstract_019e41f4-826b-7e5e-88ac-16fed589ee6d" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleExcludingAccruedInterest_019e41f4-826b-77a1-b64b-84a69a950594" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HeldToMaturitySecuritiesAbstract_019e41f4-826b-74b5-b48a-4138405e57fa" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_HeldToMaturitySecuritiesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfGainLossOnInvestmentsIncludingMarketableSecuritiesAndInvestmentsHeldAtCostIncomeStatementReportedAmountsSummaryLineItems_019e41f4-826b-7921-b808-6f02236e86c9" xlink:to="loc_us-gaap_HeldToMaturitySecuritiesAbstract_019e41f4-826b-74b5-b48a-4138405e57fa" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesHeldToMaturityExcludingAccruedInterestBeforeAllowanceForCreditLoss_019e41f4-826b-7bc3-bce2-d74c1d98235d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtSecuritiesHeldToMaturityExcludingAccruedInterestBeforeAllowanceForCreditLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HeldToMaturitySecuritiesAbstract_019e41f4-826b-74b5-b48a-4138405e57fa" xlink:to="loc_us-gaap_DebtSecuritiesHeldToMaturityExcludingAccruedInterestBeforeAllowanceForCreditLoss_019e41f4-826b-7bc3-bce2-d74c1d98235d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesHeldToMaturityAllowanceForCreditLossExcludingAccruedInterest_019e41f4-826b-7f18-9cf1-7c492aea02e5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtSecuritiesHeldToMaturityAllowanceForCreditLossExcludingAccruedInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HeldToMaturitySecuritiesAbstract_019e41f4-826b-74b5-b48a-4138405e57fa" xlink:to="loc_us-gaap_DebtSecuritiesHeldToMaturityAllowanceForCreditLossExcludingAccruedInterest_019e41f4-826b-7f18-9cf1-7c492aea02e5" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesHeldToMaturityExcludingAccruedInterestAfterAllowanceForCreditLoss_019e41f4-826b-7657-9f1c-101aeb0c89ae" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtSecuritiesHeldToMaturityExcludingAccruedInterestAfterAllowanceForCreditLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HeldToMaturitySecuritiesAbstract_019e41f4-826b-74b5-b48a-4138405e57fa" xlink:to="loc_us-gaap_DebtSecuritiesHeldToMaturityExcludingAccruedInterestAfterAllowanceForCreditLoss_019e41f4-826b-7657-9f1c-101aeb0c89ae" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingGain_019e41f4-826b-7edc-a559-4f5507c0f776" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingGain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HeldToMaturitySecuritiesAbstract_019e41f4-826b-74b5-b48a-4138405e57fa" xlink:to="loc_us-gaap_HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingGain_019e41f4-826b-7edc-a559-4f5507c0f776" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingLoss_019e41f4-826b-7f6b-a3ff-bc17b674f785" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HeldToMaturitySecuritiesAbstract_019e41f4-826b-74b5-b48a-4138405e57fa" xlink:to="loc_us-gaap_HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingLoss_019e41f4-826b-7f6b-a3ff-bc17b674f785" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HeldToMaturitySecuritiesFairValue_019e41f4-826b-75a9-9500-676f1be3561e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_HeldToMaturitySecuritiesFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HeldToMaturitySecuritiesAbstract_019e41f4-826b-74b5-b48a-4138405e57fa" xlink:to="loc_us-gaap_HeldToMaturitySecuritiesFairValue_019e41f4-826b-75a9-9500-676f1be3561e" xlink:type="arc" order="6"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.firstmerchants.com/role/INVESTMENTSECURITIESNarrativeDetails" xlink:type="simple" xlink:href="frme-20260630.xsd#INVESTMENTSECURITIESNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.firstmerchants.com/role/INVESTMENTSECURITIESNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_frme_ScheduleOfAvailableForSaleSecuritiesAndHeldToMaturitySecuritiesLineItems_019e41f4-826b-7002-9022-748a72da84bc" xlink:href="frme-20260630.xsd#frme_ScheduleOfAvailableForSaleSecuritiesAndHeldToMaturitySecuritiesLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_ScheduleOfAvailableForSaleSecuritiesAndHeldToMaturitySecuritiesTable_019e41f4-826b-7a2d-824f-5e2a50307fc5" xlink:href="frme-20260630.xsd#frme_ScheduleOfAvailableForSaleSecuritiesAndHeldToMaturitySecuritiesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_frme_ScheduleOfAvailableForSaleSecuritiesAndHeldToMaturitySecuritiesLineItems_019e41f4-826b-7002-9022-748a72da84bc" xlink:to="loc_frme_ScheduleOfAvailableForSaleSecuritiesAndHeldToMaturitySecuritiesTable_019e41f4-826b-7a2d-824f-5e2a50307fc5" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentAxis_019e41f4-826b-7113-b778-e84725c9f2e8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancialInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_frme_ScheduleOfAvailableForSaleSecuritiesAndHeldToMaturitySecuritiesTable_019e41f4-826b-7a2d-824f-5e2a50307fc5" xlink:to="loc_us-gaap_FinancialInstrumentAxis_019e41f4-826b-7113-b778-e84725c9f2e8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e41f4-826b-7113-b778-e84725c9f2e8_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentAxis_019e41f4-826b-7113-b778-e84725c9f2e8" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e41f4-826b-7113-b778-e84725c9f2e8_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e41f4-826b-71f2-bb41-842fb9015cc2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentAxis_019e41f4-826b-7113-b778-e84725c9f2e8" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e41f4-826b-71f2-bb41-842fb9015cc2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_USStatesAndPoliticalSubdivisionsMember_019e41f4-826b-75c7-959f-319aa99695c9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_USStatesAndPoliticalSubdivisionsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e41f4-826b-71f2-bb41-842fb9015cc2" xlink:to="loc_us-gaap_USStatesAndPoliticalSubdivisionsMember_019e41f4-826b-75c7-959f-319aa99695c9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_DebtSecuritiesAvailableForSaleAndHeldToMaturityAccruedInterest_019e41f4-826b-7ba4-9b73-f355ad0c7d9d" xlink:href="frme-20260630.xsd#frme_DebtSecuritiesAvailableForSaleAndHeldToMaturityAccruedInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_frme_ScheduleOfAvailableForSaleSecuritiesAndHeldToMaturitySecuritiesLineItems_019e41f4-826b-7002-9022-748a72da84bc" xlink:to="loc_frme_DebtSecuritiesAvailableForSaleAndHeldToMaturityAccruedInterest_019e41f4-826b-7ba4-9b73-f355ad0c7d9d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesHeldToMaturityAllowanceForCreditLossExcludingAccruedInterest_019e41f4-826b-7ea2-9ca2-9ba87935ad8c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtSecuritiesHeldToMaturityAllowanceForCreditLossExcludingAccruedInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_frme_ScheduleOfAvailableForSaleSecuritiesAndHeldToMaturitySecuritiesLineItems_019e41f4-826b-7002-9022-748a72da84bc" xlink:to="loc_us-gaap_DebtSecuritiesHeldToMaturityAllowanceForCreditLossExcludingAccruedInterest_019e41f4-826b-7ea2-9ca2-9ba87935ad8c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_SecuritiesPledgedAsCollateral_019e41f4-826b-7b56-aa84-9857420f9079" xlink:href="frme-20260630.xsd#frme_SecuritiesPledgedAsCollateral"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_frme_ScheduleOfAvailableForSaleSecuritiesAndHeldToMaturitySecuritiesLineItems_019e41f4-826b-7002-9022-748a72da84bc" xlink:to="loc_frme_SecuritiesPledgedAsCollateral_019e41f4-826b-7b56-aa84-9857420f9079" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SecuritiesSoldUnderAgreementsToRepurchaseAsset_019e41f4-826b-7cc1-bd01-e2a3c7d2ffe6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SecuritiesSoldUnderAgreementsToRepurchaseAsset"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_frme_ScheduleOfAvailableForSaleSecuritiesAndHeldToMaturitySecuritiesLineItems_019e41f4-826b-7002-9022-748a72da84bc" xlink:to="loc_us-gaap_SecuritiesSoldUnderAgreementsToRepurchaseAsset_019e41f4-826b-7cc1-bd01-e2a3c7d2ffe6" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.firstmerchants.com/role/INVESTMENTSECURITIESSummaryofAmortizedCostofInvestmentSecuritiesHeldtoMaturityAggregatedbyCreditQualityIndicatorDetails" xlink:type="simple" xlink:href="frme-20260630.xsd#INVESTMENTSECURITIESSummaryofAmortizedCostofInvestmentSecuritiesHeldtoMaturityAggregatedbyCreditQualityIndicatorDetails"/>
  <link:definitionLink xlink:role="http://www.firstmerchants.com/role/INVESTMENTSECURITIESSummaryofAmortizedCostofInvestmentSecuritiesHeldtoMaturityAggregatedbyCreditQualityIndicatorDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfHeldToMaturitySecuritiesLineItems_019e41f4-832c-7bb2-beb5-560e2d043169" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfHeldToMaturitySecuritiesLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfHeldToMaturitySecuritiesTable_019e41f4-826b-7ac4-a1f5-10e8ae45979a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfHeldToMaturitySecuritiesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ScheduleOfHeldToMaturitySecuritiesLineItems_019e41f4-832c-7bb2-beb5-560e2d043169" xlink:to="loc_us-gaap_ScheduleOfHeldToMaturitySecuritiesTable_019e41f4-826b-7ac4-a1f5-10e8ae45979a" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentAxis_019e41f4-826b-772e-bc2b-89c225f4e37d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancialInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfHeldToMaturitySecuritiesTable_019e41f4-826b-7ac4-a1f5-10e8ae45979a" xlink:to="loc_us-gaap_FinancialInstrumentAxis_019e41f4-826b-772e-bc2b-89c225f4e37d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e41f4-826b-772e-bc2b-89c225f4e37d_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentAxis_019e41f4-826b-772e-bc2b-89c225f4e37d" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e41f4-826b-772e-bc2b-89c225f4e37d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e41f4-826b-7cb8-9eb9-5ce337f08521" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentAxis_019e41f4-826b-772e-bc2b-89c225f4e37d" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e41f4-826b-7cb8-9eb9-5ce337f08521" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_USGovernmentAgenciesDebtSecuritiesMember_019e41f4-826b-7439-a5e6-ffe0e30ff3a5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_USGovernmentAgenciesDebtSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e41f4-826b-7cb8-9eb9-5ce337f08521" xlink:to="loc_us-gaap_USGovernmentAgenciesDebtSecuritiesMember_019e41f4-826b-7439-a5e6-ffe0e30ff3a5" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_USStatesAndPoliticalSubdivisionsMember_019e41f4-826b-77d0-b47a-56063304a612" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_USStatesAndPoliticalSubdivisionsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e41f4-826b-7cb8-9eb9-5ce337f08521" xlink:to="loc_us-gaap_USStatesAndPoliticalSubdivisionsMember_019e41f4-826b-77d0-b47a-56063304a612" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember_019e41f4-826b-7609-b314-b48cd552ff49" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e41f4-826b-7cb8-9eb9-5ce337f08521" xlink:to="loc_us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember_019e41f4-826b-7609-b314-b48cd552ff49" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CreditRatingMoodysAxis_019e41f4-832c-71df-b096-a56b9320e3a8" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_CreditRatingMoodysAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfHeldToMaturitySecuritiesTable_019e41f4-826b-7ac4-a1f5-10e8ae45979a" xlink:to="loc_srt_CreditRatingMoodysAxis_019e41f4-832c-71df-b096-a56b9320e3a8" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ExternalCreditRatingMoodysMember_019e41f4-832c-71df-b096-a56b9320e3a8_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ExternalCreditRatingMoodysMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_CreditRatingMoodysAxis_019e41f4-832c-71df-b096-a56b9320e3a8" xlink:to="loc_srt_ExternalCreditRatingMoodysMember_019e41f4-832c-71df-b096-a56b9320e3a8_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ExternalCreditRatingMoodysMember_019e41f4-832c-7a45-9b90-2774a0ab15de" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ExternalCreditRatingMoodysMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_CreditRatingMoodysAxis_019e41f4-832c-71df-b096-a56b9320e3a8" xlink:to="loc_srt_ExternalCreditRatingMoodysMember_019e41f4-832c-7a45-9b90-2774a0ab15de" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MoodysAaaRatingMember_019e41f4-832c-75e6-b1af-ace4ef6fb5d1" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_MoodysAaaRatingMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ExternalCreditRatingMoodysMember_019e41f4-832c-7a45-9b90-2774a0ab15de" xlink:to="loc_srt_MoodysAaaRatingMember_019e41f4-832c-75e6-b1af-ace4ef6fb5d1" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MoodysAa1RatingMember_019e41f4-832c-74e2-9f18-2f69a1cf8444" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_MoodysAa1RatingMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ExternalCreditRatingMoodysMember_019e41f4-832c-7a45-9b90-2774a0ab15de" xlink:to="loc_srt_MoodysAa1RatingMember_019e41f4-832c-74e2-9f18-2f69a1cf8444" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MoodysAa2RatingMember_019e41f4-832c-71fd-ac53-504041e370f4" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_MoodysAa2RatingMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ExternalCreditRatingMoodysMember_019e41f4-832c-7a45-9b90-2774a0ab15de" xlink:to="loc_srt_MoodysAa2RatingMember_019e41f4-832c-71fd-ac53-504041e370f4" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MoodysAa3RatingMember_019e41f4-832c-75a5-85cc-20c486db5609" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_MoodysAa3RatingMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ExternalCreditRatingMoodysMember_019e41f4-832c-7a45-9b90-2774a0ab15de" xlink:to="loc_srt_MoodysAa3RatingMember_019e41f4-832c-75a5-85cc-20c486db5609" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MoodysA1RatingMember_019e41f4-832c-7d44-872b-54297cf6fc1d" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_MoodysA1RatingMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ExternalCreditRatingMoodysMember_019e41f4-832c-7a45-9b90-2774a0ab15de" xlink:to="loc_srt_MoodysA1RatingMember_019e41f4-832c-7d44-872b-54297cf6fc1d" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MoodysA2RatingMember_019e41f4-832c-72da-b314-a57490da59c2" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_MoodysA2RatingMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ExternalCreditRatingMoodysMember_019e41f4-832c-7a45-9b90-2774a0ab15de" xlink:to="loc_srt_MoodysA2RatingMember_019e41f4-832c-72da-b314-a57490da59c2" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MoodysA3RatingMember_019e41f4-832c-71a6-b0d1-5cd44eb6c2d2" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_MoodysA3RatingMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ExternalCreditRatingMoodysMember_019e41f4-832c-7a45-9b90-2774a0ab15de" xlink:to="loc_srt_MoodysA3RatingMember_019e41f4-832c-71a6-b0d1-5cd44eb6c2d2" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_NonRatedMember_019e41f4-832c-783a-9604-cdf492d3f60a" xlink:href="frme-20260630.xsd#frme_NonRatedMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ExternalCreditRatingMoodysMember_019e41f4-832c-7a45-9b90-2774a0ab15de" xlink:to="loc_frme_NonRatedMember_019e41f4-832c-783a-9604-cdf492d3f60a" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesHeldToMaturityExcludingAccruedInterestBeforeAllowanceForCreditLoss_019e41f4-832c-7d67-b9b7-2b074a40f74d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtSecuritiesHeldToMaturityExcludingAccruedInterestBeforeAllowanceForCreditLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfHeldToMaturitySecuritiesLineItems_019e41f4-832c-7bb2-beb5-560e2d043169" xlink:to="loc_us-gaap_DebtSecuritiesHeldToMaturityExcludingAccruedInterestBeforeAllowanceForCreditLoss_019e41f4-832c-7d67-b9b7-2b074a40f74d" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.firstmerchants.com/role/INVESTMENTSECURITIESSummaryofInvestmentSecuritiesinaContinuousUnrealizedLossPositionDetails" xlink:type="simple" xlink:href="frme-20260630.xsd#INVESTMENTSECURITIESSummaryofInvestmentSecuritiesinaContinuousUnrealizedLossPositionDetails"/>
  <link:definitionLink xlink:role="http://www.firstmerchants.com/role/INVESTMENTSECURITIESSummaryofInvestmentSecuritiesinaContinuousUnrealizedLossPositionDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfInvestmentsLineItems_019e41f4-832d-7fa7-ab68-ee98409804e8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfInvestmentsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfInvestmentsTable_019e41f4-832c-7bf5-8fc0-871224aef111" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfInvestmentsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ScheduleOfInvestmentsLineItems_019e41f4-832d-7fa7-ab68-ee98409804e8" xlink:to="loc_us-gaap_ScheduleOfInvestmentsTable_019e41f4-832c-7bf5-8fc0-871224aef111" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentAxis_019e41f4-832d-796f-81e8-7786529f22dd" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancialInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfInvestmentsTable_019e41f4-832c-7bf5-8fc0-871224aef111" xlink:to="loc_us-gaap_FinancialInstrumentAxis_019e41f4-832d-796f-81e8-7786529f22dd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e41f4-832d-796f-81e8-7786529f22dd_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentAxis_019e41f4-832d-796f-81e8-7786529f22dd" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e41f4-832d-796f-81e8-7786529f22dd_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e41f4-832d-702c-8fb4-0193ca7f94a3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentAxis_019e41f4-832d-796f-81e8-7786529f22dd" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e41f4-832d-702c-8fb4-0193ca7f94a3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_USGovernmentAgenciesDebtSecuritiesMember_019e41f4-832d-7e86-8554-ca3a753856bd" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_USGovernmentAgenciesDebtSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e41f4-832d-702c-8fb4-0193ca7f94a3" xlink:to="loc_us-gaap_USGovernmentAgenciesDebtSecuritiesMember_019e41f4-832d-7e86-8554-ca3a753856bd" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_USStatesAndPoliticalSubdivisionsMember_019e41f4-832d-7eaf-9a8c-4af0a986aab1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_USStatesAndPoliticalSubdivisionsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e41f4-832d-702c-8fb4-0193ca7f94a3" xlink:to="loc_us-gaap_USStatesAndPoliticalSubdivisionsMember_019e41f4-832d-7eaf-9a8c-4af0a986aab1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember_019e41f4-832d-7883-a949-bfde6a127bd2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e41f4-832d-702c-8fb4-0193ca7f94a3" xlink:to="loc_us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember_019e41f4-832d-7883-a949-bfde6a127bd2" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CorporateDebtSecuritiesMember_019e41f4-832d-7904-a3e7-650c622a3d79" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CorporateDebtSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e41f4-832d-702c-8fb4-0193ca7f94a3" xlink:to="loc_us-gaap_CorporateDebtSecuritiesMember_019e41f4-832d-7904-a3e7-650c622a3d79" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesFairValueToAmortizedCostBasisAbstract_019e41f4-832d-7f4d-bf42-aa2a094b8c70" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AvailableForSaleSecuritiesFairValueToAmortizedCostBasisAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfInvestmentsLineItems_019e41f4-832d-7fa7-ab68-ee98409804e8" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesFairValueToAmortizedCostBasisAbstract_019e41f4-832d-7f4d-bf42-aa2a094b8c70" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months_019e41f4-832d-762b-bdc0-f19baf231791" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesFairValueToAmortizedCostBasisAbstract_019e41f4-832d-7f4d-bf42-aa2a094b8c70" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months_019e41f4-832d-762b-bdc0-f19baf231791" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger_019e41f4-832d-7a01-ae91-d9b1867b43da" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesFairValueToAmortizedCostBasisAbstract_019e41f4-832d-7f4d-bf42-aa2a094b8c70" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger_019e41f4-832d-7a01-ae91-d9b1867b43da" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPosition_019e41f4-832d-7e48-9cc9-0c5b16c7f5aa" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPosition"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesFairValueToAmortizedCostBasisAbstract_019e41f4-832d-7f4d-bf42-aa2a094b8c70" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPosition_019e41f4-832d-7e48-9cc9-0c5b16c7f5aa" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionAccumulatedLossAbstract_019e41f4-832d-7caa-a47b-71e09e138fb5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionAccumulatedLossAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfInvestmentsLineItems_019e41f4-832d-7fa7-ab68-ee98409804e8" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionAccumulatedLossAbstract_019e41f4-832d-7caa-a47b-71e09e138fb5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss_019e41f4-832d-70e2-be45-c29647ec88b4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionAccumulatedLossAbstract_019e41f4-832d-7caa-a47b-71e09e138fb5" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss_019e41f4-832d-70e2-be45-c29647ec88b4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss_019e41f4-832d-7f1c-be1e-8b38053522de" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionAccumulatedLossAbstract_019e41f4-832d-7caa-a47b-71e09e138fb5" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss_019e41f4-832d-7f1c-be1e-8b38053522de" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss_019e41f4-832d-7810-9b75-43176cbd507e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionAccumulatedLossAbstract_019e41f4-832d-7caa-a47b-71e09e138fb5" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss_019e41f4-832d-7810-9b75-43176cbd507e" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionNumberOfPositions_019e41f4-832d-7120-a63f-d88bc3a9a1f8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionNumberOfPositions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionAccumulatedLossAbstract_019e41f4-832d-7caa-a47b-71e09e138fb5" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionNumberOfPositions_019e41f4-832d-7120-a63f-d88bc3a9a1f8" xlink:type="arc" order="4"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.firstmerchants.com/role/INVESTMENTSECURITIESSummaryofInvestmentsinDebtandEquitySecuritiesReportedintheFinancialStatementsatanAmountLessThanTheirHistoricalCostDetails" xlink:type="simple" xlink:href="frme-20260630.xsd#INVESTMENTSECURITIESSummaryofInvestmentsinDebtandEquitySecuritiesReportedintheFinancialStatementsatanAmountLessThanTheirHistoricalCostDetails"/>
  <link:definitionLink xlink:role="http://www.firstmerchants.com/role/INVESTMENTSECURITIESSummaryofInvestmentsinDebtandEquitySecuritiesReportedintheFinancialStatementsatanAmountLessThanTheirHistoricalCostDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfInvestmentsLineItems_019e41f4-832d-795e-8d19-f616964580ba" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfInvestmentsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfInvestmentsTable_019e41f4-832d-75ab-b8e3-7380ea7d591d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfInvestmentsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ScheduleOfInvestmentsLineItems_019e41f4-832d-795e-8d19-f616964580ba" xlink:to="loc_us-gaap_ScheduleOfInvestmentsTable_019e41f4-832d-75ab-b8e3-7380ea7d591d" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentAxis_019e41f4-832d-7213-933d-ae9629e9f777" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancialInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfInvestmentsTable_019e41f4-832d-75ab-b8e3-7380ea7d591d" xlink:to="loc_us-gaap_FinancialInstrumentAxis_019e41f4-832d-7213-933d-ae9629e9f777" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e41f4-832d-7213-933d-ae9629e9f777_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentAxis_019e41f4-832d-7213-933d-ae9629e9f777" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e41f4-832d-7213-933d-ae9629e9f777_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e41f4-832d-7672-ab30-2b63b248a79a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentAxis_019e41f4-832d-7213-933d-ae9629e9f777" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e41f4-832d-7672-ab30-2b63b248a79a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_InvestmentsInDebtAndEquitySecuritiesReportedAtLessThanHistoricalCostMember_019e41f4-832d-7d04-9bff-f315418ce7c9" xlink:href="frme-20260630.xsd#frme_InvestmentsInDebtAndEquitySecuritiesReportedAtLessThanHistoricalCostMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e41f4-832d-7672-ab30-2b63b248a79a" xlink:to="loc_frme_InvestmentsInDebtAndEquitySecuritiesReportedAtLessThanHistoricalCostMember_019e41f4-832d-7d04-9bff-f315418ce7c9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_InvestmentHistoricalCost_019e41f4-832d-75e0-8394-e03005ce1895" xlink:href="frme-20260630.xsd#frme_InvestmentHistoricalCost"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfInvestmentsLineItems_019e41f4-832d-795e-8d19-f616964580ba" xlink:to="loc_frme_InvestmentHistoricalCost_019e41f4-832d-75e0-8394-e03005ce1895" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_SecuritiesContinuousUnrealizedLossPositionFairValue_019e41f4-832d-7001-b292-0d080e5c159e" xlink:href="frme-20260630.xsd#frme_SecuritiesContinuousUnrealizedLossPositionFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfInvestmentsLineItems_019e41f4-832d-795e-8d19-f616964580ba" xlink:to="loc_frme_SecuritiesContinuousUnrealizedLossPositionFairValue_019e41f4-832d-7001-b292-0d080e5c159e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_SecuritiesContinuousUnrealizedLossPositionAccumulatedLoss_019e41f4-832d-7ba5-81c2-4afdd3eba3f6" xlink:href="frme-20260630.xsd#frme_SecuritiesContinuousUnrealizedLossPositionAccumulatedLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfInvestmentsLineItems_019e41f4-832d-795e-8d19-f616964580ba" xlink:to="loc_frme_SecuritiesContinuousUnrealizedLossPositionAccumulatedLoss_019e41f4-832d-7ba5-81c2-4afdd3eba3f6" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_PercentageOfTotalInvestmentPortfolioFairValue_019e41f4-832d-7716-999e-194ce756e13a" xlink:href="frme-20260630.xsd#frme_PercentageOfTotalInvestmentPortfolioFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfInvestmentsLineItems_019e41f4-832d-795e-8d19-f616964580ba" xlink:to="loc_frme_PercentageOfTotalInvestmentPortfolioFairValue_019e41f4-832d-7716-999e-194ce756e13a" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.firstmerchants.com/role/INVESTMENTSECURITIESSummaryofAmortizedCostandFairValueofAvailableforSaleSecuritiesandHeldtoMaturitySecuritiesbyContractualMaturityDetails" xlink:type="simple" xlink:href="frme-20260630.xsd#INVESTMENTSECURITIESSummaryofAmortizedCostandFairValueofAvailableforSaleSecuritiesandHeldtoMaturitySecuritiesbyContractualMaturityDetails"/>
  <link:definitionLink xlink:role="http://www.firstmerchants.com/role/INVESTMENTSECURITIESSummaryofAmortizedCostandFairValueofAvailableforSaleSecuritiesandHeldtoMaturitySecuritiesbyContractualMaturityDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_frme_ScheduleOfAvailableForSaleSecuritiesAndHeldToMaturitySecuritiesLineItems_019e41f4-832d-73a6-8be6-a2f3f8cfbcbb" xlink:href="frme-20260630.xsd#frme_ScheduleOfAvailableForSaleSecuritiesAndHeldToMaturitySecuritiesLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_ScheduleOfAvailableForSaleSecuritiesAndHeldToMaturitySecuritiesTable_019e41f4-832d-795c-9921-14158767102d" xlink:href="frme-20260630.xsd#frme_ScheduleOfAvailableForSaleSecuritiesAndHeldToMaturitySecuritiesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_frme_ScheduleOfAvailableForSaleSecuritiesAndHeldToMaturitySecuritiesLineItems_019e41f4-832d-73a6-8be6-a2f3f8cfbcbb" xlink:to="loc_frme_ScheduleOfAvailableForSaleSecuritiesAndHeldToMaturitySecuritiesTable_019e41f4-832d-795c-9921-14158767102d" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentAxis_019e41f4-832d-7406-b00e-2195406ff405" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancialInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_frme_ScheduleOfAvailableForSaleSecuritiesAndHeldToMaturitySecuritiesTable_019e41f4-832d-795c-9921-14158767102d" xlink:to="loc_us-gaap_FinancialInstrumentAxis_019e41f4-832d-7406-b00e-2195406ff405" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e41f4-832d-7406-b00e-2195406ff405_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentAxis_019e41f4-832d-7406-b00e-2195406ff405" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e41f4-832d-7406-b00e-2195406ff405_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e41f4-832d-7344-8848-723f6c521f46" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentAxis_019e41f4-832d-7406-b00e-2195406ff405" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e41f4-832d-7344-8848-723f6c521f46" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember_019e41f4-832d-77f0-90a0-f0d9c66eca69" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e41f4-832d-7344-8848-723f6c521f46" xlink:to="loc_us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember_019e41f4-832d-77f0-90a0-f0d9c66eca69" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAbstract_019e41f4-832d-752a-8ec2-08e7400bd573" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_frme_ScheduleOfAvailableForSaleSecuritiesAndHeldToMaturitySecuritiesLineItems_019e41f4-832d-73a6-8be6-a2f3f8cfbcbb" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAbstract_019e41f4-832d-752a-8ec2-08e7400bd573" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDateAmortizedCostBasisRollingMaturityAbstract_019e41f4-832d-7a6d-a773-fd452b6472fa" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDateAmortizedCostBasisRollingMaturityAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAbstract_019e41f4-832d-752a-8ec2-08e7400bd573" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDateAmortizedCostBasisRollingMaturityAbstract_019e41f4-832d-7a6d-a773-fd452b6472fa" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesNextRollingTwelveMonthsAmortizedCostBasis_019e41f4-832d-70c3-9d75-c7c67154f2af" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesNextRollingTwelveMonthsAmortizedCostBasis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDateAmortizedCostBasisRollingMaturityAbstract_019e41f4-832d-7a6d-a773-fd452b6472fa" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesNextRollingTwelveMonthsAmortizedCostBasis_019e41f4-832d-70c3-9d75-c7c67154f2af" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesRollingYearTwoThroughFiveAmortizedCostBasis_019e41f4-832d-7110-8897-df263f5f7b7d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesRollingYearTwoThroughFiveAmortizedCostBasis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDateAmortizedCostBasisRollingMaturityAbstract_019e41f4-832d-7a6d-a773-fd452b6472fa" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesRollingYearTwoThroughFiveAmortizedCostBasis_019e41f4-832d-7110-8897-df263f5f7b7d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesRollingYearSixThroughTenAmortizedCostBasis_019e41f4-832d-7ea5-9c74-32412d6017e5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesRollingYearSixThroughTenAmortizedCostBasis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDateAmortizedCostBasisRollingMaturityAbstract_019e41f4-832d-7a6d-a773-fd452b6472fa" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesRollingYearSixThroughTenAmortizedCostBasis_019e41f4-832d-7ea5-9c74-32412d6017e5" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesRollingAfterYearTenAmortizedCostBasis_019e41f4-832d-7a32-9f83-cfc57384e352" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesRollingAfterYearTenAmortizedCostBasis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDateAmortizedCostBasisRollingMaturityAbstract_019e41f4-832d-7a6d-a773-fd452b6472fa" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesRollingAfterYearTenAmortizedCostBasis_019e41f4-832d-7a32-9f83-cfc57384e352" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDateAmortizedCostBasis_019e41f4-832d-7f3a-b62d-abb1d195f258" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDateAmortizedCostBasis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDateAmortizedCostBasisRollingMaturityAbstract_019e41f4-832d-7a6d-a773-fd452b6472fa" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDateAmortizedCostBasis_019e41f4-832d-7f3a-b62d-abb1d195f258" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithoutSingleMaturityDateAmortizedCost_019e41f4-832d-76e2-8480-ba735293814d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithoutSingleMaturityDateAmortizedCost"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDateAmortizedCostBasisRollingMaturityAbstract_019e41f4-832d-7a6d-a773-fd452b6472fa" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithoutSingleMaturityDateAmortizedCost_019e41f4-832d-76e2-8480-ba735293814d" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleAndHeldToMaturityAmortizedCostBeforeAllowanceForCreditLoss_019e41f4-832d-7c18-9eaa-c31f5a7c1f94" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtSecuritiesAvailableForSaleAndHeldToMaturityAmortizedCostBeforeAllowanceForCreditLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDateAmortizedCostBasisRollingMaturityAbstract_019e41f4-832d-7a6d-a773-fd452b6472fa" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleAndHeldToMaturityAmortizedCostBeforeAllowanceForCreditLoss_019e41f4-832d-7c18-9eaa-c31f5a7c1f94" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDateRollingMaturityAbstract_019e41f4-832d-727c-99c4-5ec972e17878" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDateRollingMaturityAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAbstract_019e41f4-832d-752a-8ec2-08e7400bd573" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDateRollingMaturityAbstract_019e41f4-832d-727c-99c4-5ec972e17878" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesNextRollingTwelveMonthsFairValue_019e41f4-832d-7bb8-9555-584bf0115e68" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesNextRollingTwelveMonthsFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDateRollingMaturityAbstract_019e41f4-832d-727c-99c4-5ec972e17878" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesNextRollingTwelveMonthsFairValue_019e41f4-832d-7bb8-9555-584bf0115e68" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesRollingYearTwoThroughFiveFairValue_019e41f4-832d-7aff-99aa-1fab78aa7b24" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesRollingYearTwoThroughFiveFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDateRollingMaturityAbstract_019e41f4-832d-727c-99c4-5ec972e17878" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesRollingYearTwoThroughFiveFairValue_019e41f4-832d-7aff-99aa-1fab78aa7b24" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesRollingYearSixThroughTenFairValue_019e41f4-832d-705e-8a11-c4ae13e418e1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesRollingYearSixThroughTenFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDateRollingMaturityAbstract_019e41f4-832d-727c-99c4-5ec972e17878" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesRollingYearSixThroughTenFairValue_019e41f4-832d-705e-8a11-c4ae13e418e1" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesRollingAfterYearTenFairValue_019e41f4-832d-7fd0-9981-9c846b601b34" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesRollingAfterYearTenFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDateRollingMaturityAbstract_019e41f4-832d-727c-99c4-5ec972e17878" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesRollingAfterYearTenFairValue_019e41f4-832d-7fd0-9981-9c846b601b34" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDate_019e41f4-832d-781f-bb42-ed81f7831789" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDateRollingMaturityAbstract_019e41f4-832d-727c-99c4-5ec972e17878" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDate_019e41f4-832d-781f-bb42-ed81f7831789" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithoutSingleMaturityDateFairValue_019e41f4-832d-7699-9870-95c3c6885b05" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithoutSingleMaturityDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDateRollingMaturityAbstract_019e41f4-832d-727c-99c4-5ec972e17878" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithoutSingleMaturityDateFairValue_019e41f4-832d-7699-9870-95c3c6885b05" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleExcludingAccruedInterest_019e41f4-832d-736f-a37a-bc47eb6f734b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtSecuritiesAvailableForSaleExcludingAccruedInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDateRollingMaturityAbstract_019e41f4-832d-727c-99c4-5ec972e17878" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleExcludingAccruedInterest_019e41f4-832d-736f-a37a-bc47eb6f734b" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HeldToMaturitySecuritiesDebtMaturitiesFairValueRollingMaturityAbstract_019e41f4-832d-71f8-a34c-57ccd2501f9e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_HeldToMaturitySecuritiesDebtMaturitiesFairValueRollingMaturityAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_frme_ScheduleOfAvailableForSaleSecuritiesAndHeldToMaturitySecuritiesLineItems_019e41f4-832d-73a6-8be6-a2f3f8cfbcbb" xlink:to="loc_us-gaap_HeldToMaturitySecuritiesDebtMaturitiesFairValueRollingMaturityAbstract_019e41f4-832d-71f8-a34c-57ccd2501f9e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HeldToMaturitySecuritiesDebtMaturitiesSingleMaturityDateAmortizedCostBasisAbstract_019e41f4-832d-768c-a2ff-e2a358b2803b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_HeldToMaturitySecuritiesDebtMaturitiesSingleMaturityDateAmortizedCostBasisAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HeldToMaturitySecuritiesDebtMaturitiesFairValueRollingMaturityAbstract_019e41f4-832d-71f8-a34c-57ccd2501f9e" xlink:to="loc_us-gaap_HeldToMaturitySecuritiesDebtMaturitiesSingleMaturityDateAmortizedCostBasisAbstract_019e41f4-832d-768c-a2ff-e2a358b2803b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HeldtomaturitySecuritiesDebtMaturitiesNextRollingTwelveMonthsAmortizedCost_019e41f4-832d-7aa3-be5c-e896b5a72948" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_HeldtomaturitySecuritiesDebtMaturitiesNextRollingTwelveMonthsAmortizedCost"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HeldToMaturitySecuritiesDebtMaturitiesSingleMaturityDateAmortizedCostBasisAbstract_019e41f4-832d-768c-a2ff-e2a358b2803b" xlink:to="loc_us-gaap_HeldtomaturitySecuritiesDebtMaturitiesNextRollingTwelveMonthsAmortizedCost_019e41f4-832d-7aa3-be5c-e896b5a72948" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HeldtomaturitySecuritiesDebtMaturitiesRollingYearTwoThroughFiveAmortizedCost_019e41f4-832d-70d7-9220-e337604989f8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_HeldtomaturitySecuritiesDebtMaturitiesRollingYearTwoThroughFiveAmortizedCost"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HeldToMaturitySecuritiesDebtMaturitiesSingleMaturityDateAmortizedCostBasisAbstract_019e41f4-832d-768c-a2ff-e2a358b2803b" xlink:to="loc_us-gaap_HeldtomaturitySecuritiesDebtMaturitiesRollingYearTwoThroughFiveAmortizedCost_019e41f4-832d-70d7-9220-e337604989f8" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HeldtomaturitySecuritiesDebtMaturitiesRollingYearSixThroughTenAmortizedCost_019e41f4-832d-7f1b-b5e9-7d6c3f419554" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_HeldtomaturitySecuritiesDebtMaturitiesRollingYearSixThroughTenAmortizedCost"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HeldToMaturitySecuritiesDebtMaturitiesSingleMaturityDateAmortizedCostBasisAbstract_019e41f4-832d-768c-a2ff-e2a358b2803b" xlink:to="loc_us-gaap_HeldtomaturitySecuritiesDebtMaturitiesRollingYearSixThroughTenAmortizedCost_019e41f4-832d-7f1b-b5e9-7d6c3f419554" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HeldtomaturitySecuritiesDebtMaturitiesRollingAfterTenYearsAmortizedCost_019e41f4-832d-7c62-984d-1bf7574386bc" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_HeldtomaturitySecuritiesDebtMaturitiesRollingAfterTenYearsAmortizedCost"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HeldToMaturitySecuritiesDebtMaturitiesSingleMaturityDateAmortizedCostBasisAbstract_019e41f4-832d-768c-a2ff-e2a358b2803b" xlink:to="loc_us-gaap_HeldtomaturitySecuritiesDebtMaturitiesRollingAfterTenYearsAmortizedCost_019e41f4-832d-7c62-984d-1bf7574386bc" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HeldToMaturitySecuritiesDebtMaturitiesSingleMaturityDateAmortizedCostBasis_019e41f4-832d-79aa-8a3a-742221fe66d8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_HeldToMaturitySecuritiesDebtMaturitiesSingleMaturityDateAmortizedCostBasis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HeldToMaturitySecuritiesDebtMaturitiesSingleMaturityDateAmortizedCostBasisAbstract_019e41f4-832d-768c-a2ff-e2a358b2803b" xlink:to="loc_us-gaap_HeldToMaturitySecuritiesDebtMaturitiesSingleMaturityDateAmortizedCostBasis_019e41f4-832d-79aa-8a3a-742221fe66d8" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HeldToMaturitySecuritiesDebtMaturitiesWithoutSingleMaturityDateNetCarryingAmount_019e41f4-832d-7ac2-ae42-0559a882c5ed" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_HeldToMaturitySecuritiesDebtMaturitiesWithoutSingleMaturityDateNetCarryingAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HeldToMaturitySecuritiesDebtMaturitiesSingleMaturityDateAmortizedCostBasisAbstract_019e41f4-832d-768c-a2ff-e2a358b2803b" xlink:to="loc_us-gaap_HeldToMaturitySecuritiesDebtMaturitiesWithoutSingleMaturityDateNetCarryingAmount_019e41f4-832d-7ac2-ae42-0559a882c5ed" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesHeldToMaturityExcludingAccruedInterestBeforeAllowanceForCreditLoss_019e41f4-832d-7d55-8bfa-2b58436c398d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtSecuritiesHeldToMaturityExcludingAccruedInterestBeforeAllowanceForCreditLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HeldToMaturitySecuritiesDebtMaturitiesSingleMaturityDateAmortizedCostBasisAbstract_019e41f4-832d-768c-a2ff-e2a358b2803b" xlink:to="loc_us-gaap_DebtSecuritiesHeldToMaturityExcludingAccruedInterestBeforeAllowanceForCreditLoss_019e41f4-832d-7d55-8bfa-2b58436c398d" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HeldToMaturitySecuritiesDebtMaturitiesSingleMaturityDateFairValueRollingMaturityAbstract_019e41f4-832d-70e9-ae34-2e69f8bbafbd" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_HeldToMaturitySecuritiesDebtMaturitiesSingleMaturityDateFairValueRollingMaturityAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HeldToMaturitySecuritiesDebtMaturitiesFairValueRollingMaturityAbstract_019e41f4-832d-71f8-a34c-57ccd2501f9e" xlink:to="loc_us-gaap_HeldToMaturitySecuritiesDebtMaturitiesSingleMaturityDateFairValueRollingMaturityAbstract_019e41f4-832d-70e9-ae34-2e69f8bbafbd" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HeldToMaturitySecuritiesDebtMaturitiesNextRollingTwelveMonthsFairValue_019e41f4-832d-702e-8095-a18f709d1957" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_HeldToMaturitySecuritiesDebtMaturitiesNextRollingTwelveMonthsFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HeldToMaturitySecuritiesDebtMaturitiesSingleMaturityDateFairValueRollingMaturityAbstract_019e41f4-832d-70e9-ae34-2e69f8bbafbd" xlink:to="loc_us-gaap_HeldToMaturitySecuritiesDebtMaturitiesNextRollingTwelveMonthsFairValue_019e41f4-832d-702e-8095-a18f709d1957" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HeldToMaturitySecuritiesDebtMaturitiesRollingYearTwoThroughFiveFairValue_019e41f4-832d-7228-b058-912006fe4783" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_HeldToMaturitySecuritiesDebtMaturitiesRollingYearTwoThroughFiveFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HeldToMaturitySecuritiesDebtMaturitiesSingleMaturityDateFairValueRollingMaturityAbstract_019e41f4-832d-70e9-ae34-2e69f8bbafbd" xlink:to="loc_us-gaap_HeldToMaturitySecuritiesDebtMaturitiesRollingYearTwoThroughFiveFairValue_019e41f4-832d-7228-b058-912006fe4783" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HeldToMaturitySecuritiesDebtMaturitiesRollingYearSixThroughTenFairValue_019e41f4-832d-73a9-b07b-a3b74c8c9428" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_HeldToMaturitySecuritiesDebtMaturitiesRollingYearSixThroughTenFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HeldToMaturitySecuritiesDebtMaturitiesSingleMaturityDateFairValueRollingMaturityAbstract_019e41f4-832d-70e9-ae34-2e69f8bbafbd" xlink:to="loc_us-gaap_HeldToMaturitySecuritiesDebtMaturitiesRollingYearSixThroughTenFairValue_019e41f4-832d-73a9-b07b-a3b74c8c9428" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HeldToMaturitySecuritiesDebtMaturitiesRollingAfterTenYearsFairValue_019e41f4-832d-7871-8c33-db19f4e3092d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_HeldToMaturitySecuritiesDebtMaturitiesRollingAfterTenYearsFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HeldToMaturitySecuritiesDebtMaturitiesSingleMaturityDateFairValueRollingMaturityAbstract_019e41f4-832d-70e9-ae34-2e69f8bbafbd" xlink:to="loc_us-gaap_HeldToMaturitySecuritiesDebtMaturitiesRollingAfterTenYearsFairValue_019e41f4-832d-7871-8c33-db19f4e3092d" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HeldToMaturitySecuritiesDebtMaturitiesSingleMaturityDateFairValue_019e41f4-832d-7059-a63b-6fa8624676c2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_HeldToMaturitySecuritiesDebtMaturitiesSingleMaturityDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HeldToMaturitySecuritiesDebtMaturitiesSingleMaturityDateFairValueRollingMaturityAbstract_019e41f4-832d-70e9-ae34-2e69f8bbafbd" xlink:to="loc_us-gaap_HeldToMaturitySecuritiesDebtMaturitiesSingleMaturityDateFairValue_019e41f4-832d-7059-a63b-6fa8624676c2" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HeldToMaturitySecuritiesDebtMaturitiesWithoutSingleMaturityDateFairValue_019e41f4-832d-7412-a170-b0f45178e6e8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_HeldToMaturitySecuritiesDebtMaturitiesWithoutSingleMaturityDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HeldToMaturitySecuritiesDebtMaturitiesSingleMaturityDateFairValueRollingMaturityAbstract_019e41f4-832d-70e9-ae34-2e69f8bbafbd" xlink:to="loc_us-gaap_HeldToMaturitySecuritiesDebtMaturitiesWithoutSingleMaturityDateFairValue_019e41f4-832d-7412-a170-b0f45178e6e8" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HeldToMaturitySecuritiesFairValue_019e41f4-832d-7aaf-83f9-91f38c5137f3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_HeldToMaturitySecuritiesFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HeldToMaturitySecuritiesDebtMaturitiesSingleMaturityDateFairValueRollingMaturityAbstract_019e41f4-832d-70e9-ae34-2e69f8bbafbd" xlink:to="loc_us-gaap_HeldToMaturitySecuritiesFairValue_019e41f4-832d-7aaf-83f9-91f38c5137f3" xlink:type="arc" order="7"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.firstmerchants.com/role/LOANSANDALLOWANCEFORCREDITLOSSESSummaryofCompositionofLoanPortfoliobyLoanClassDetails" xlink:type="simple" xlink:href="frme-20260630.xsd#LOANSANDALLOWANCEFORCREDITLOSSESSummaryofCompositionofLoanPortfoliobyLoanClassDetails"/>
  <link:definitionLink xlink:role="http://www.firstmerchants.com/role/LOANSANDALLOWANCEFORCREDITLOSSESSummaryofCompositionofLoanPortfoliobyLoanClassDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_019e41f4-832d-7536-b9e8-eb695e73f4f2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableRecordedInvestmentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable_019e41f4-832d-76ca-9c8a-2e254a1df1fb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_019e41f4-832d-7536-b9e8-eb695e73f4f2" xlink:to="loc_us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable_019e41f4-832d-76ca-9c8a-2e254a1df1fb" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019e41f4-832d-7597-8f45-d04688b022aa" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable_019e41f4-832d-76ca-9c8a-2e254a1df1fb" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019e41f4-832d-7597-8f45-d04688b022aa" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e41f4-832d-7597-8f45-d04688b022aa_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019e41f4-832d-7597-8f45-d04688b022aa" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e41f4-832d-7597-8f45-d04688b022aa_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e41f4-832d-7bfd-9239-c5b3b1fd956a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019e41f4-832d-7597-8f45-d04688b022aa" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e41f4-832d-7bfd-9239-c5b3b1fd956a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_CommercialAndIndustrialLoansMember_019e41f4-832d-78a9-8a02-fb289d8d0711" xlink:href="frme-20260630.xsd#frme_CommercialAndIndustrialLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e41f4-832d-7bfd-9239-c5b3b1fd956a" xlink:to="loc_frme_CommercialAndIndustrialLoansMember_019e41f4-832d-78a9-8a02-fb289d8d0711" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_FarmingAndAgricultureMember_019e41f4-832d-7669-ae30-5b49ba068578" xlink:href="frme-20260630.xsd#frme_FarmingAndAgricultureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e41f4-832d-7bfd-9239-c5b3b1fd956a" xlink:to="loc_frme_FarmingAndAgricultureMember_019e41f4-832d-7669-ae30-5b49ba068578" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConstructionLoansMember_019e41f4-832d-76ba-b587-b426c5172833" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConstructionLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e41f4-832d-7bfd-9239-c5b3b1fd956a" xlink:to="loc_us-gaap_ConstructionLoansMember_019e41f4-832d-76ba-b587-b426c5172833" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_CommercialRealEstateNonOwnerOccupiedMember_019e41f4-832d-77be-957d-79e909124abb" xlink:href="frme-20260630.xsd#frme_CommercialRealEstateNonOwnerOccupiedMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e41f4-832d-7bfd-9239-c5b3b1fd956a" xlink:to="loc_frme_CommercialRealEstateNonOwnerOccupiedMember_019e41f4-832d-77be-957d-79e909124abb" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_CommercialRealEstateOwnerOccupiedMember_019e41f4-832d-7b8e-bb14-54fe461f9973" xlink:href="frme-20260630.xsd#frme_CommercialRealEstateOwnerOccupiedMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e41f4-832d-7bfd-9239-c5b3b1fd956a" xlink:to="loc_frme_CommercialRealEstateOwnerOccupiedMember_019e41f4-832d-7b8e-bb14-54fe461f9973" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ResidentialRealEstateMember_019e41f4-832d-7dea-bc3e-28a2d557c4dd" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ResidentialRealEstateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e41f4-832d-7bfd-9239-c5b3b1fd956a" xlink:to="loc_us-gaap_ResidentialRealEstateMember_019e41f4-832d-7dea-bc3e-28a2d557c4dd" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HomeEquityLoanMember_019e41f4-832d-754e-a737-10071d9ae30a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_HomeEquityLoanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e41f4-832d-7bfd-9239-c5b3b1fd956a" xlink:to="loc_us-gaap_HomeEquityLoanMember_019e41f4-832d-754e-a737-10071d9ae30a" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConsumerLoanMember_019e41f4-832d-779f-b8a6-292eef0e5807" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConsumerLoanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e41f4-832d-7bfd-9239-c5b3b1fd956a" xlink:to="loc_us-gaap_ConsumerLoanMember_019e41f4-832d-779f-b8a6-292eef0e5807" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_PublicFinanceAndOtherCommercialLoansMember_019e41f4-832d-726b-9d6c-67534dbd24bb" xlink:href="frme-20260630.xsd#frme_PublicFinanceAndOtherCommercialLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e41f4-832d-7bfd-9239-c5b3b1fd956a" xlink:to="loc_frme_PublicFinanceAndOtherCommercialLoansMember_019e41f4-832d-726b-9d6c-67534dbd24bb" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss_019e41f4-832d-71cd-b3ae-e020c4afc6cc" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_019e41f4-832d-7536-b9e8-eb695e73f4f2" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss_019e41f4-832d-71cd-b3ae-e020c4afc6cc" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.firstmerchants.com/role/LOANSANDALLOWANCEFORCREDITLOSSESSummaryofRiskGradingofLoanPortfoliobyLoanClassDetails" xlink:type="simple" xlink:href="frme-20260630.xsd#LOANSANDALLOWANCEFORCREDITLOSSESSummaryofRiskGradingofLoanPortfoliobyLoanClassDetails"/>
  <link:definitionLink xlink:role="http://www.firstmerchants.com/role/LOANSANDALLOWANCEFORCREDITLOSSESSummaryofRiskGradingofLoanPortfoliobyLoanClassDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_019e41f4-832d-7382-b3dd-15303776f3b3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccountsNotesAndLoansReceivableLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_019e41f4-832d-7375-8213-83cd9db2a365" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_019e41f4-832d-7382-b3dd-15303776f3b3" xlink:to="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_019e41f4-832d-7375-8213-83cd9db2a365" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019e41f4-832d-726c-9131-018a4c700b27" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_019e41f4-832d-7375-8213-83cd9db2a365" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019e41f4-832d-726c-9131-018a4c700b27" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e41f4-832d-726c-9131-018a4c700b27_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019e41f4-832d-726c-9131-018a4c700b27" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e41f4-832d-726c-9131-018a4c700b27_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e41f4-832d-7f97-b29e-f61c2344a9f9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019e41f4-832d-726c-9131-018a4c700b27" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e41f4-832d-7f97-b29e-f61c2344a9f9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_CommercialAndIndustrialLoansMember_019e41f4-832d-7417-ac22-dab3bf7bcda3" xlink:href="frme-20260630.xsd#frme_CommercialAndIndustrialLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e41f4-832d-7f97-b29e-f61c2344a9f9" xlink:to="loc_frme_CommercialAndIndustrialLoansMember_019e41f4-832d-7417-ac22-dab3bf7bcda3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_FarmingAndAgricultureMember_019e41f4-832d-714f-895a-5f9a8b519f98" xlink:href="frme-20260630.xsd#frme_FarmingAndAgricultureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e41f4-832d-7f97-b29e-f61c2344a9f9" xlink:to="loc_frme_FarmingAndAgricultureMember_019e41f4-832d-714f-895a-5f9a8b519f98" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConstructionLoansMember_019e41f4-832d-7e6d-ab9a-427f7c37a2bc" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConstructionLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e41f4-832d-7f97-b29e-f61c2344a9f9" xlink:to="loc_us-gaap_ConstructionLoansMember_019e41f4-832d-7e6d-ab9a-427f7c37a2bc" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_CommercialRealEstateNonOwnerOccupiedMember_019e41f4-832d-7c2e-bc4c-662b88efc362" xlink:href="frme-20260630.xsd#frme_CommercialRealEstateNonOwnerOccupiedMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e41f4-832d-7f97-b29e-f61c2344a9f9" xlink:to="loc_frme_CommercialRealEstateNonOwnerOccupiedMember_019e41f4-832d-7c2e-bc4c-662b88efc362" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_CommercialRealEstateOwnerOccupiedMember_019e41f4-832d-7427-8efc-e2011f41b972" xlink:href="frme-20260630.xsd#frme_CommercialRealEstateOwnerOccupiedMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e41f4-832d-7f97-b29e-f61c2344a9f9" xlink:to="loc_frme_CommercialRealEstateOwnerOccupiedMember_019e41f4-832d-7427-8efc-e2011f41b972" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ResidentialRealEstateMember_019e41f4-832d-7d00-b6f3-7344f5f2aed3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ResidentialRealEstateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e41f4-832d-7f97-b29e-f61c2344a9f9" xlink:to="loc_us-gaap_ResidentialRealEstateMember_019e41f4-832d-7d00-b6f3-7344f5f2aed3" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HomeEquityLoanMember_019e41f4-832d-7260-8c45-2800391d9474" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_HomeEquityLoanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e41f4-832d-7f97-b29e-f61c2344a9f9" xlink:to="loc_us-gaap_HomeEquityLoanMember_019e41f4-832d-7260-8c45-2800391d9474" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConsumerLoanMember_019e41f4-832d-78a3-b130-9856ccc42cac" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConsumerLoanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e41f4-832d-7f97-b29e-f61c2344a9f9" xlink:to="loc_us-gaap_ConsumerLoanMember_019e41f4-832d-78a3-b130-9856ccc42cac" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_PublicFinanceAndOtherCommercialLoansMember_019e41f4-832d-7641-b33a-dec1014215c0" xlink:href="frme-20260630.xsd#frme_PublicFinanceAndOtherCommercialLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e41f4-832d-7f97-b29e-f61c2344a9f9" xlink:to="loc_frme_PublicFinanceAndOtherCommercialLoansMember_019e41f4-832d-7641-b33a-dec1014215c0" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InternalCreditAssessmentAxis_019e41f4-832d-7bab-b1ff-1c5e7e37d4a5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InternalCreditAssessmentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_019e41f4-832d-7375-8213-83cd9db2a365" xlink:to="loc_us-gaap_InternalCreditAssessmentAxis_019e41f4-832d-7bab-b1ff-1c5e7e37d4a5" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InternalCreditAssessmentDomain_019e41f4-832d-7bab-b1ff-1c5e7e37d4a5_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InternalCreditAssessmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_InternalCreditAssessmentAxis_019e41f4-832d-7bab-b1ff-1c5e7e37d4a5" xlink:to="loc_us-gaap_InternalCreditAssessmentDomain_019e41f4-832d-7bab-b1ff-1c5e7e37d4a5_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InternalCreditAssessmentDomain_019e41f4-832d-7dfc-a93c-6806a4bdd12a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InternalCreditAssessmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_InternalCreditAssessmentAxis_019e41f4-832d-7bab-b1ff-1c5e7e37d4a5" xlink:to="loc_us-gaap_InternalCreditAssessmentDomain_019e41f4-832d-7dfc-a93c-6806a4bdd12a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PassMember_019e41f4-832d-76d3-954e-6ada5111e3a2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PassMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InternalCreditAssessmentDomain_019e41f4-832d-7dfc-a93c-6806a4bdd12a" xlink:to="loc_us-gaap_PassMember_019e41f4-832d-76d3-954e-6ada5111e3a2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SpecialMentionMember_019e41f4-832d-7ab9-9a18-2e668c83de75" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SpecialMentionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InternalCreditAssessmentDomain_019e41f4-832d-7dfc-a93c-6806a4bdd12a" xlink:to="loc_us-gaap_SpecialMentionMember_019e41f4-832d-7ab9-9a18-2e668c83de75" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubstandardMember_019e41f4-832d-74ee-8496-e7a23cc4865f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubstandardMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InternalCreditAssessmentDomain_019e41f4-832d-7dfc-a93c-6806a4bdd12a" xlink:to="loc_us-gaap_SubstandardMember_019e41f4-832d-74ee-8496-e7a23cc4865f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DoubtfulMember_019e41f4-832d-745c-9f09-81049c54c2e2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DoubtfulMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InternalCreditAssessmentDomain_019e41f4-832d-7dfc-a93c-6806a4bdd12a" xlink:to="loc_us-gaap_DoubtfulMember_019e41f4-832d-745c-9f09-81049c54c2e2" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestYearOneOriginatedCurrentFiscalYear_019e41f4-832d-742f-89a9-406dbc3d9d9f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestYearOneOriginatedCurrentFiscalYear"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_019e41f4-832d-7382-b3dd-15303776f3b3" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestYearOneOriginatedCurrentFiscalYear_019e41f4-832d-742f-89a9-406dbc3d9d9f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestYearOneOriginatedCurrentFiscalYearWriteoff_019e41f4-832d-70f1-8f84-c62e13c9380c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestYearOneOriginatedCurrentFiscalYearWriteoff"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_019e41f4-832d-7382-b3dd-15303776f3b3" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestYearOneOriginatedCurrentFiscalYearWriteoff_019e41f4-832d-70f1-8f84-c62e13c9380c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestYearTwoOriginatedFiscalYearBeforeCurrentFiscalYear_019e41f4-832d-75b6-acdf-0e38ef1bf7a6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestYearTwoOriginatedFiscalYearBeforeCurrentFiscalYear"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_019e41f4-832d-7382-b3dd-15303776f3b3" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestYearTwoOriginatedFiscalYearBeforeCurrentFiscalYear_019e41f4-832d-75b6-acdf-0e38ef1bf7a6" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestYearTwoOriginatedFiscalYearBeforeCurrentFiscalYearWriteoff_019e41f4-832d-70c1-ad9f-82aa7e88ae66" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestYearTwoOriginatedFiscalYearBeforeCurrentFiscalYearWriteoff"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_019e41f4-832d-7382-b3dd-15303776f3b3" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestYearTwoOriginatedFiscalYearBeforeCurrentFiscalYearWriteoff_019e41f4-832d-70c1-ad9f-82aa7e88ae66" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestYearThreeOriginatedTwoYearsBeforeCurrentFiscalYear_019e41f4-832d-77fd-813f-b6c0416196c1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestYearThreeOriginatedTwoYearsBeforeCurrentFiscalYear"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_019e41f4-832d-7382-b3dd-15303776f3b3" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestYearThreeOriginatedTwoYearsBeforeCurrentFiscalYear_019e41f4-832d-77fd-813f-b6c0416196c1" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestYearThreeOriginatedTwoYearsBeforeCurrentFiscalYearWriteoff_019e41f4-832d-7734-8264-09db68ccd3b2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestYearThreeOriginatedTwoYearsBeforeCurrentFiscalYearWriteoff"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_019e41f4-832d-7382-b3dd-15303776f3b3" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestYearThreeOriginatedTwoYearsBeforeCurrentFiscalYearWriteoff_019e41f4-832d-7734-8264-09db68ccd3b2" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestYearFourOriginatedThreeYearsBeforeCurrentFiscalYear_019e41f4-832d-7fbd-b73e-b902b33b6cb1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestYearFourOriginatedThreeYearsBeforeCurrentFiscalYear"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_019e41f4-832d-7382-b3dd-15303776f3b3" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestYearFourOriginatedThreeYearsBeforeCurrentFiscalYear_019e41f4-832d-7fbd-b73e-b902b33b6cb1" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestYearFourOriginatedThreeYearsBeforeCurrentFiscalYearWriteoff_019e41f4-832d-75ca-b327-d860ae91b9e3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestYearFourOriginatedThreeYearsBeforeCurrentFiscalYearWriteoff"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_019e41f4-832d-7382-b3dd-15303776f3b3" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestYearFourOriginatedThreeYearsBeforeCurrentFiscalYearWriteoff_019e41f4-832d-75ca-b327-d860ae91b9e3" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestYearFiveOriginatedFourYearsBeforeCurrentFiscalYear_019e41f4-832d-7faf-b187-ca287689408b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestYearFiveOriginatedFourYearsBeforeCurrentFiscalYear"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_019e41f4-832d-7382-b3dd-15303776f3b3" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestYearFiveOriginatedFourYearsBeforeCurrentFiscalYear_019e41f4-832d-7faf-b187-ca287689408b" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestYearFiveOriginatedFourYearsBeforeCurrentFiscalYearWriteoff_019e41f4-832d-7096-9ced-35463530d062" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestYearFiveOriginatedFourYearsBeforeCurrentFiscalYearWriteoff"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_019e41f4-832d-7382-b3dd-15303776f3b3" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestYearFiveOriginatedFourYearsBeforeCurrentFiscalYearWriteoff_019e41f4-832d-7096-9ced-35463530d062" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestOriginatedMoreThanFiveYearsBeforeCurrentFiscalYear_019e41f4-832d-7132-abb3-aae2a163f96b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestOriginatedMoreThanFiveYearsBeforeCurrentFiscalYear"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_019e41f4-832d-7382-b3dd-15303776f3b3" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestOriginatedMoreThanFiveYearsBeforeCurrentFiscalYear_019e41f4-832d-7132-abb3-aae2a163f96b" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestOriginatedMoreThanFiveYearsBeforeCurrentFiscalYearWriteoff_019e41f4-832d-7d49-811b-0169d674ea0a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestOriginatedMoreThanFiveYearsBeforeCurrentFiscalYearWriteoff"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_019e41f4-832d-7382-b3dd-15303776f3b3" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestOriginatedMoreThanFiveYearsBeforeCurrentFiscalYearWriteoff_019e41f4-832d-7d49-811b-0169d674ea0a" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestRevolving_019e41f4-832d-7646-999c-7934dfc4d969" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestRevolving"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_019e41f4-832d-7382-b3dd-15303776f3b3" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestRevolving_019e41f4-832d-7646-999c-7934dfc4d969" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestRevolvingWriteoff_019e41f4-832d-7c66-ba8e-5a5b2a319c8c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestRevolvingWriteoff"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_019e41f4-832d-7382-b3dd-15303776f3b3" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestRevolvingWriteoff_019e41f4-832d-7c66-ba8e-5a5b2a319c8c" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestRevolvingConvertedToTermLoan_019e41f4-832d-79f8-a89e-f9d2a52dc915" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestRevolvingConvertedToTermLoan"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_019e41f4-832d-7382-b3dd-15303776f3b3" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestRevolvingConvertedToTermLoan_019e41f4-832d-79f8-a89e-f9d2a52dc915" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestRevolvingConvertedToTermLoanWriteoff_019e41f4-832d-7d7d-8030-707003487eb2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestRevolvingConvertedToTermLoanWriteoff"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_019e41f4-832d-7382-b3dd-15303776f3b3" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestRevolvingConvertedToTermLoanWriteoff_019e41f4-832d-7d7d-8030-707003487eb2" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss_019e41f4-832d-7f73-a3ee-904fe966b2e3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_019e41f4-832d-7382-b3dd-15303776f3b3" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss_019e41f4-832d-7f73-a3ee-904fe966b2e3" xlink:type="arc" order="16"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossWriteoff_019e41f4-832d-7548-84f1-0d6911539aab" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossWriteoff"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_019e41f4-832d-7382-b3dd-15303776f3b3" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossWriteoff_019e41f4-832d-7548-84f1-0d6911539aab" xlink:type="arc" order="17"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.firstmerchants.com/role/LOANSANDALLOWANCEFORCREDITLOSSESNarrativeDetails" xlink:type="simple" xlink:href="frme-20260630.xsd#LOANSANDALLOWANCEFORCREDITLOSSESNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.firstmerchants.com/role/LOANSANDALLOWANCEFORCREDITLOSSESNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_019e41f4-832d-75b4-8904-691e1b5dca7e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccountsNotesAndLoansReceivableLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_019e41f4-832d-76c1-aeed-513433877552" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_019e41f4-832d-75b4-8904-691e1b5dca7e" xlink:to="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_019e41f4-832d-76c1-aeed-513433877552" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablesPeriodPastDueAxis_019e41f4-832d-7f5d-bece-faefe6bdc77b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivablesPeriodPastDueAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_019e41f4-832d-76c1-aeed-513433877552" xlink:to="loc_us-gaap_FinancingReceivablesPeriodPastDueAxis_019e41f4-832d-7f5d-bece-faefe6bdc77b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablesPeriodPastDueDomain_019e41f4-832d-7f5d-bece-faefe6bdc77b_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivablesPeriodPastDueDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivablesPeriodPastDueAxis_019e41f4-832d-7f5d-bece-faefe6bdc77b" xlink:to="loc_us-gaap_FinancingReceivablesPeriodPastDueDomain_019e41f4-832d-7f5d-bece-faefe6bdc77b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablesPeriodPastDueDomain_019e41f4-832d-7a5a-9611-319569b2ec9c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivablesPeriodPastDueDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivablesPeriodPastDueAxis_019e41f4-832d-7f5d-bece-faefe6bdc77b" xlink:to="loc_us-gaap_FinancingReceivablesPeriodPastDueDomain_019e41f4-832d-7a5a-9611-319569b2ec9c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialAssetPastDueMember_019e41f4-832d-732d-8f56-4bceb9ff8c83" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancialAssetPastDueMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablesPeriodPastDueDomain_019e41f4-832d-7a5a-9611-319569b2ec9c" xlink:to="loc_us-gaap_FinancialAssetPastDueMember_019e41f4-832d-732d-8f56-4bceb9ff8c83" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivables30To59DaysPastDueMember_019e41f4-832d-723f-b430-7e906bacbf53" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivables30To59DaysPastDueMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablesPeriodPastDueDomain_019e41f4-832d-7a5a-9611-319569b2ec9c" xlink:to="loc_us-gaap_FinancingReceivables30To59DaysPastDueMember_019e41f4-832d-723f-b430-7e906bacbf53" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivables60To89DaysPastDueMember_019e41f4-832d-7268-af0b-21bd400b6fd3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivables60To89DaysPastDueMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablesPeriodPastDueDomain_019e41f4-832d-7a5a-9611-319569b2ec9c" xlink:to="loc_us-gaap_FinancingReceivables60To89DaysPastDueMember_019e41f4-832d-7268-af0b-21bd400b6fd3" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablesEqualToGreaterThan90DaysPastDueMember_019e41f4-832d-765a-b16b-91fff3e0465a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivablesEqualToGreaterThan90DaysPastDueMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablesPeriodPastDueDomain_019e41f4-832d-7a5a-9611-319569b2ec9c" xlink:to="loc_us-gaap_FinancingReceivablesEqualToGreaterThan90DaysPastDueMember_019e41f4-832d-765a-b16b-91fff3e0465a" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019e41f4-832d-7dc8-aae2-3f1691a5c217" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_019e41f4-832d-76c1-aeed-513433877552" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019e41f4-832d-7dc8-aae2-3f1691a5c217" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e41f4-832d-7dc8-aae2-3f1691a5c217_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019e41f4-832d-7dc8-aae2-3f1691a5c217" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e41f4-832d-7dc8-aae2-3f1691a5c217_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e41f4-832d-7a31-b1bd-8c396f4b7ade" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019e41f4-832d-7dc8-aae2-3f1691a5c217" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e41f4-832d-7a31-b1bd-8c396f4b7ade" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_CommercialAndIndustrialLoansMember_019e41f4-832d-7cd5-a732-e0e2bea0a005" xlink:href="frme-20260630.xsd#frme_CommercialAndIndustrialLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e41f4-832d-7a31-b1bd-8c396f4b7ade" xlink:to="loc_frme_CommercialAndIndustrialLoansMember_019e41f4-832d-7cd5-a732-e0e2bea0a005" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConstructionLoansMember_019e41f4-832d-7ce4-8aab-fc3004dd1bdb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConstructionLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e41f4-832d-7a31-b1bd-8c396f4b7ade" xlink:to="loc_us-gaap_ConstructionLoansMember_019e41f4-832d-7ce4-8aab-fc3004dd1bdb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_ResidentialAndCommercialRealEstateMember_019e41f4-832d-7eb8-a1e0-8abb29447749" xlink:href="frme-20260630.xsd#frme_ResidentialAndCommercialRealEstateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e41f4-832d-7a31-b1bd-8c396f4b7ade" xlink:to="loc_frme_ResidentialAndCommercialRealEstateMember_019e41f4-832d-7eb8-a1e0-8abb29447749" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_CommercialRealEstateOwnerOccupiedMember_019e41f4-832d-724a-8607-d70c4e0e9ae8" xlink:href="frme-20260630.xsd#frme_CommercialRealEstateOwnerOccupiedMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e41f4-832d-7a31-b1bd-8c396f4b7ade" xlink:to="loc_frme_CommercialRealEstateOwnerOccupiedMember_019e41f4-832d-724a-8607-d70c4e0e9ae8" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HomeEquityLoanMember_019e41f4-832d-7a46-b427-f8acaaf7a301" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_HomeEquityLoanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e41f4-832d-7a31-b1bd-8c396f4b7ade" xlink:to="loc_us-gaap_HomeEquityLoanMember_019e41f4-832d-7a46-b427-f8acaaf7a301" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_CommercialRealEstateNonOwnerOccupiedMember_019e41f4-832d-7a82-a819-d7d7afacee2e" xlink:href="frme-20260630.xsd#frme_CommercialRealEstateNonOwnerOccupiedMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e41f4-832d-7a31-b1bd-8c396f4b7ade" xlink:to="loc_frme_CommercialRealEstateNonOwnerOccupiedMember_019e41f4-832d-7a82-a819-d7d7afacee2e" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_OwnerOccupiedResidentialLoansMember_019e41f4-832d-76c1-88d2-1f9ff77d91b5" xlink:href="frme-20260630.xsd#frme_OwnerOccupiedResidentialLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e41f4-832d-7a31-b1bd-8c396f4b7ade" xlink:to="loc_frme_OwnerOccupiedResidentialLoansMember_019e41f4-832d-76c1-88d2-1f9ff77d91b5" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ResidentialRealEstateMember_019f8271-c07e-78bc-ba35-29603e527f59" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ResidentialRealEstateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e41f4-832d-7a31-b1bd-8c396f4b7ade" xlink:to="loc_us-gaap_ResidentialRealEstateMember_019f8271-c07e-78bc-ba35-29603e527f59" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CollateralAxis_019e41f4-832d-7f4f-bea4-2755b4aa7b41" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CollateralAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_019e41f4-832d-76c1-aeed-513433877552" xlink:to="loc_us-gaap_CollateralAxis_019e41f4-832d-7f4f-bea4-2755b4aa7b41" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CollateralDomain_019e41f4-832d-7f4f-bea4-2755b4aa7b41_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CollateralDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CollateralAxis_019e41f4-832d-7f4f-bea4-2755b4aa7b41" xlink:to="loc_us-gaap_CollateralDomain_019e41f4-832d-7f4f-bea4-2755b4aa7b41_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CollateralDomain_019e41f4-832d-72db-9804-92e8c7139d75" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CollateralDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CollateralAxis_019e41f4-832d-7f4f-bea4-2755b4aa7b41" xlink:to="loc_us-gaap_CollateralDomain_019e41f4-832d-72db-9804-92e8c7139d75" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CollateralPledgedMember_019e41f4-832d-795a-bd2f-e4f050dcc922" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CollateralPledgedMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CollateralDomain_019e41f4-832d-72db-9804-92e8c7139d75" xlink:to="loc_us-gaap_CollateralPledgedMember_019e41f4-832d-795a-bd2f-e4f050dcc922" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_019e41f4-832d-7ea7-8d09-52963bc10849" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessAcquisitionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_019e41f4-832d-76c1-aeed-513433877552" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_019e41f4-832d-7ea7-8d09-52963bc10849" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_019e41f4-832d-7ea7-8d09-52963bc10849_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_019e41f4-832d-7ea7-8d09-52963bc10849" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_019e41f4-832d-7ea7-8d09-52963bc10849_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_019e41f4-832d-7d00-b1b0-6ec21b292d6e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_019e41f4-832d-7ea7-8d09-52963bc10849" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_019e41f4-832d-7d00-b1b0-6ec21b292d6e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_FirstSavingsFinancialGroupInc.Member_019e41f4-832d-74de-86fa-309947bb8200" xlink:href="frme-20260630.xsd#frme_FirstSavingsFinancialGroupInc.Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_019e41f4-832d-7d00-b1b0-6ec21b292d6e" xlink:to="loc_frme_FirstSavingsFinancialGroupInc.Member_019e41f4-832d-74de-86fa-309947bb8200" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfFinancingReceivableTypeOfBorrowerAxis_019e41f4-832d-7a6b-a8b4-e0eb00d47dc1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfFinancingReceivableTypeOfBorrowerAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_019e41f4-832d-76c1-aeed-513433877552" xlink:to="loc_us-gaap_ClassOfFinancingReceivableTypeOfBorrowerAxis_019e41f4-832d-7a6b-a8b4-e0eb00d47dc1" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfFinancingReceivableTypeOfBorrowerDomain_019e41f4-832d-7a6b-a8b4-e0eb00d47dc1_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfFinancingReceivableTypeOfBorrowerDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ClassOfFinancingReceivableTypeOfBorrowerAxis_019e41f4-832d-7a6b-a8b4-e0eb00d47dc1" xlink:to="loc_us-gaap_ClassOfFinancingReceivableTypeOfBorrowerDomain_019e41f4-832d-7a6b-a8b4-e0eb00d47dc1_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfFinancingReceivableTypeOfBorrowerDomain_019e41f4-832d-7f12-a568-fb6f6488617b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfFinancingReceivableTypeOfBorrowerDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ClassOfFinancingReceivableTypeOfBorrowerAxis_019e41f4-832d-7a6b-a8b4-e0eb00d47dc1" xlink:to="loc_us-gaap_ClassOfFinancingReceivableTypeOfBorrowerDomain_019e41f4-832d-7f12-a568-fb6f6488617b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_PerformingResidentialMortgageLoansMember_019e41f4-832d-70d7-8d74-324d6cfa3bf3" xlink:href="frme-20260630.xsd#frme_PerformingResidentialMortgageLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfFinancingReceivableTypeOfBorrowerDomain_019e41f4-832d-7f12-a568-fb6f6488617b" xlink:to="loc_frme_PerformingResidentialMortgageLoansMember_019e41f4-832d-70d7-8d74-324d6cfa3bf3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss_019e41f4-832d-7eb4-8e44-c204fae88373" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_019e41f4-832d-75b4-8904-691e1b5dca7e" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss_019e41f4-832d-7eb4-8e44-c204fae88373" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_FinancingReceivablePastDueIncreaseDecrease_019e41f4-832d-7f62-9cf0-c93ce9e97378" xlink:href="frme-20260630.xsd#frme_FinancingReceivablePastDueIncreaseDecrease"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_019e41f4-832d-75b4-8904-691e1b5dca7e" xlink:to="loc_frme_FinancingReceivablePastDueIncreaseDecrease_019e41f4-832d-7f62-9cf0-c93ce9e97378" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_FinancingReceivableNonaccrualIncreaseDecrease_019fa185-eaeb-7d8c-b3fb-eccb3c872cb6" xlink:href="frme-20260630.xsd#frme_FinancingReceivableNonaccrualIncreaseDecrease"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_019e41f4-832d-75b4-8904-691e1b5dca7e" xlink:to="loc_frme_FinancingReceivableNonaccrualIncreaseDecrease_019fa185-eaeb-7d8c-b3fb-eccb3c872cb6" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_FinancingReceivableNumberOfLoansPlacedOnNonaccrualStatus_019fa188-57e5-7a19-88a9-21614c73e40f" xlink:href="frme-20260630.xsd#frme_FinancingReceivableNumberOfLoansPlacedOnNonaccrualStatus"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_019e41f4-832d-75b4-8904-691e1b5dca7e" xlink:to="loc_frme_FinancingReceivableNumberOfLoansPlacedOnNonaccrualStatus_019fa188-57e5-7a19-88a9-21614c73e40f" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableNonaccrualInterestIncome_019e41f4-832d-738c-84f8-99aa4cb20692" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableNonaccrualInterestIncome"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_019e41f4-832d-75b4-8904-691e1b5dca7e" xlink:to="loc_us-gaap_FinancingReceivableNonaccrualInterestIncome_019e41f4-832d-738c-84f8-99aa4cb20692" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_FinancingReceivableIncreaseDecreaseIndividuallyEvaluatedForCreditLoss_019e41f4-832d-7597-aa5a-0b10ea910cfa" xlink:href="frme-20260630.xsd#frme_FinancingReceivableIncreaseDecreaseIndividuallyEvaluatedForCreditLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_019e41f4-832d-75b4-8904-691e1b5dca7e" xlink:to="loc_frme_FinancingReceivableIncreaseDecreaseIndividuallyEvaluatedForCreditLoss_019e41f4-832d-7597-aa5a-0b10ea910cfa" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_FinancingReceivableIncreaseDecreaseIndividuallyEvaluatedForCreditLossAllowanceForCreditLoss_019e41f4-832d-787e-bb41-045a13f920d8" xlink:href="frme-20260630.xsd#frme_FinancingReceivableIncreaseDecreaseIndividuallyEvaluatedForCreditLossAllowanceForCreditLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_019e41f4-832d-75b4-8904-691e1b5dca7e" xlink:to="loc_frme_FinancingReceivableIncreaseDecreaseIndividuallyEvaluatedForCreditLossAllowanceForCreditLoss_019e41f4-832d-787e-bb41-045a13f920d8" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableModificationsSubsequentDefaultRecordedInvestment1_019e41f4-832d-724d-a542-76c9686eb16f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableModificationsSubsequentDefaultRecordedInvestment1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_019e41f4-832d-75b4-8904-691e1b5dca7e" xlink:to="loc_us-gaap_FinancingReceivableModificationsSubsequentDefaultRecordedInvestment1_019e41f4-832d-724d-a542-76c9686eb16f" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_NumberOfLoanSegments_019e41f4-832d-7137-a25c-8086a6b32871" xlink:href="frme-20260630.xsd#frme_NumberOfLoanSegments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_019e41f4-832d-75b4-8904-691e1b5dca7e" xlink:to="loc_frme_NumberOfLoanSegments_019e41f4-832d-7137-a25c-8086a6b32871" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossPeriodIncreaseDecrease_019e41f4-832d-7dae-adb2-667c56f8d30a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossPeriodIncreaseDecrease"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_019e41f4-832d-75b4-8904-691e1b5dca7e" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossPeriodIncreaseDecrease_019e41f4-832d-7dae-adb2-667c56f8d30a" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest_019fa983-fb24-76b5-b459-02f8005afd69" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_019e41f4-832d-75b4-8904-691e1b5dca7e" xlink:to="loc_us-gaap_FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest_019fa983-fb24-76b5-b459-02f8005afd69" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableAllowanceForCreditLossWriteoffAfterRecovery_019e41f4-832d-7847-b7e1-1452287c48ef" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableAllowanceForCreditLossWriteoffAfterRecovery"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_019e41f4-832d-75b4-8904-691e1b5dca7e" xlink:to="loc_us-gaap_FinancingReceivableAllowanceForCreditLossWriteoffAfterRecovery_019e41f4-832d-7847-b7e1-1452287c48ef" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProvisionForLoanLossesExpensed_019e41f4-832d-748d-8c14-0e5b9769e7b0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProvisionForLoanLossesExpensed"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_019e41f4-832d-75b4-8904-691e1b5dca7e" xlink:to="loc_us-gaap_ProvisionForLoanLossesExpensed_019e41f4-832d-748d-8c14-0e5b9769e7b0" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_StandbyLettersOfCreditTerm_019e41f4-832d-7287-87bf-be705ec4ad1d" xlink:href="frme-20260630.xsd#frme_StandbyLettersOfCreditTerm"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_019e41f4-832d-75b4-8904-691e1b5dca7e" xlink:to="loc_frme_StandbyLettersOfCreditTerm_019e41f4-832d-7287-87bf-be705ec4ad1d" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OffBalanceSheetCreditLossLiabilityCreditLossExpenseReversal_019e41f4-832d-7a38-84dc-a2d50bdcf66b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OffBalanceSheetCreditLossLiabilityCreditLossExpenseReversal"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_019e41f4-832d-75b4-8904-691e1b5dca7e" xlink:to="loc_us-gaap_OffBalanceSheetCreditLossLiabilityCreditLossExpenseReversal_019e41f4-832d-7a38-84dc-a2d50bdcf66b" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LoansReceivableHeldForSaleAmount_019fa195-97a9-7df4-bad8-25b6c30e7b8f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LoansReceivableHeldForSaleAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_019e41f4-832d-75b4-8904-691e1b5dca7e" xlink:to="loc_us-gaap_LoansReceivableHeldForSaleAmount_019fa195-97a9-7df4-bad8-25b6c30e7b8f" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableReclassificationToHeldForSale_019e41f4-832d-796b-8953-3989bfa633b0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableReclassificationToHeldForSale"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_019e41f4-832d-75b4-8904-691e1b5dca7e" xlink:to="loc_us-gaap_FinancingReceivableReclassificationToHeldForSale_019e41f4-832d-796b-8953-3989bfa633b0" xlink:type="arc" order="16"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableTransferToHeldForSaleValuationAllowanceExpense_019fa97c-beeb-7809-9daf-73608884c721" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableTransferToHeldForSaleValuationAllowanceExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_019e41f4-832d-75b4-8904-691e1b5dca7e" xlink:to="loc_us-gaap_FinancingReceivableTransferToHeldForSaleValuationAllowanceExpense_019fa97c-beeb-7809-9daf-73608884c721" xlink:type="arc" order="17"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromSaleOfMortgageLoansHeldForSale_019fa197-ffde-74d9-9c41-e4767a139c44" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProceedsFromSaleOfMortgageLoansHeldForSale"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_019e41f4-832d-75b4-8904-691e1b5dca7e" xlink:to="loc_us-gaap_ProceedsFromSaleOfMortgageLoansHeldForSale_019fa197-ffde-74d9-9c41-e4767a139c44" xlink:type="arc" order="18"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransferOfLoansHeldForSaleToPortfolioLoans1_019fa199-f144-767a-ace1-1c81a20510f1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TransferOfLoansHeldForSaleToPortfolioLoans1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_019e41f4-832d-75b4-8904-691e1b5dca7e" xlink:to="loc_us-gaap_TransferOfLoansHeldForSaleToPortfolioLoans1_019fa199-f144-767a-ace1-1c81a20510f1" xlink:type="arc" order="19"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.firstmerchants.com/role/LOANSANDALLOWANCEFORCREDITLOSSESSummaryofPastDueAgingofLoanPortfoliobyLoanClassDetails" xlink:type="simple" xlink:href="frme-20260630.xsd#LOANSANDALLOWANCEFORCREDITLOSSESSummaryofPastDueAgingofLoanPortfoliobyLoanClassDetails"/>
  <link:definitionLink xlink:role="http://www.firstmerchants.com/role/LOANSANDALLOWANCEFORCREDITLOSSESSummaryofPastDueAgingofLoanPortfoliobyLoanClassDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentPastDueLineItems_019e41f4-832d-754f-a7a0-94cc21412ad1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableRecordedInvestmentPastDueLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfFinancingReceivablesPastDueTable_019e41f4-832d-729b-88ce-fdfdc718ebc8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfFinancingReceivablesPastDueTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentPastDueLineItems_019e41f4-832d-754f-a7a0-94cc21412ad1" xlink:to="loc_us-gaap_ScheduleOfFinancingReceivablesPastDueTable_019e41f4-832d-729b-88ce-fdfdc718ebc8" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019e41f4-832d-7f4a-9651-0f8314905c0a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivablesPastDueTable_019e41f4-832d-729b-88ce-fdfdc718ebc8" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019e41f4-832d-7f4a-9651-0f8314905c0a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e41f4-832d-7f4a-9651-0f8314905c0a_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019e41f4-832d-7f4a-9651-0f8314905c0a" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e41f4-832d-7f4a-9651-0f8314905c0a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e41f4-832d-7316-a9ea-71a92a2a8942" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019e41f4-832d-7f4a-9651-0f8314905c0a" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e41f4-832d-7316-a9ea-71a92a2a8942" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_CommercialAndIndustrialLoansMember_019e41f4-832d-7fee-8f26-92027523ec2f" xlink:href="frme-20260630.xsd#frme_CommercialAndIndustrialLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e41f4-832d-7316-a9ea-71a92a2a8942" xlink:to="loc_frme_CommercialAndIndustrialLoansMember_019e41f4-832d-7fee-8f26-92027523ec2f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_FarmingAndAgricultureMember_019e41f4-832d-7481-b17c-fc4cabd4715f" xlink:href="frme-20260630.xsd#frme_FarmingAndAgricultureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e41f4-832d-7316-a9ea-71a92a2a8942" xlink:to="loc_frme_FarmingAndAgricultureMember_019e41f4-832d-7481-b17c-fc4cabd4715f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConstructionLoansMember_019e41f4-832d-74cc-a332-2cbd0f392dc7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConstructionLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e41f4-832d-7316-a9ea-71a92a2a8942" xlink:to="loc_us-gaap_ConstructionLoansMember_019e41f4-832d-74cc-a332-2cbd0f392dc7" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_CommercialRealEstateNonOwnerOccupiedMember_019e41f4-832d-7f2e-a71f-3fac00321615" xlink:href="frme-20260630.xsd#frme_CommercialRealEstateNonOwnerOccupiedMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e41f4-832d-7316-a9ea-71a92a2a8942" xlink:to="loc_frme_CommercialRealEstateNonOwnerOccupiedMember_019e41f4-832d-7f2e-a71f-3fac00321615" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_CommercialRealEstateOwnerOccupiedMember_019e41f4-832d-794e-be0e-7a67cdfbd830" xlink:href="frme-20260630.xsd#frme_CommercialRealEstateOwnerOccupiedMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e41f4-832d-7316-a9ea-71a92a2a8942" xlink:to="loc_frme_CommercialRealEstateOwnerOccupiedMember_019e41f4-832d-794e-be0e-7a67cdfbd830" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ResidentialRealEstateMember_019e41f4-832d-7f21-a429-554b9d06328a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ResidentialRealEstateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e41f4-832d-7316-a9ea-71a92a2a8942" xlink:to="loc_us-gaap_ResidentialRealEstateMember_019e41f4-832d-7f21-a429-554b9d06328a" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HomeEquityLoanMember_019e41f4-832d-7766-b73f-97cdf5f66881" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_HomeEquityLoanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e41f4-832d-7316-a9ea-71a92a2a8942" xlink:to="loc_us-gaap_HomeEquityLoanMember_019e41f4-832d-7766-b73f-97cdf5f66881" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConsumerLoanMember_019e41f4-832d-77c7-ba65-edd673d6523f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConsumerLoanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e41f4-832d-7316-a9ea-71a92a2a8942" xlink:to="loc_us-gaap_ConsumerLoanMember_019e41f4-832d-77c7-ba65-edd673d6523f" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_PublicFinanceAndOtherCommercialLoansMember_019e41f4-832d-7576-a657-1316096309ca" xlink:href="frme-20260630.xsd#frme_PublicFinanceAndOtherCommercialLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e41f4-832d-7316-a9ea-71a92a2a8942" xlink:to="loc_frme_PublicFinanceAndOtherCommercialLoansMember_019e41f4-832d-7576-a657-1316096309ca" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablesPeriodPastDueAxis_019e41f4-832d-7acb-ba14-c58cf90174d8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivablesPeriodPastDueAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivablesPastDueTable_019e41f4-832d-729b-88ce-fdfdc718ebc8" xlink:to="loc_us-gaap_FinancingReceivablesPeriodPastDueAxis_019e41f4-832d-7acb-ba14-c58cf90174d8" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablesPeriodPastDueDomain_019e41f4-832d-7acb-ba14-c58cf90174d8_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivablesPeriodPastDueDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivablesPeriodPastDueAxis_019e41f4-832d-7acb-ba14-c58cf90174d8" xlink:to="loc_us-gaap_FinancingReceivablesPeriodPastDueDomain_019e41f4-832d-7acb-ba14-c58cf90174d8_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablesPeriodPastDueDomain_019e41f4-832d-7eda-9d3a-c300ccbb11a9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivablesPeriodPastDueDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivablesPeriodPastDueAxis_019e41f4-832d-7acb-ba14-c58cf90174d8" xlink:to="loc_us-gaap_FinancingReceivablesPeriodPastDueDomain_019e41f4-832d-7eda-9d3a-c300ccbb11a9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialAssetNotPastDueMember_019e41f4-832d-7e7b-ab3a-99a008315763" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancialAssetNotPastDueMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablesPeriodPastDueDomain_019e41f4-832d-7eda-9d3a-c300ccbb11a9" xlink:to="loc_us-gaap_FinancialAssetNotPastDueMember_019e41f4-832d-7e7b-ab3a-99a008315763" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivables30To59DaysPastDueMember_019e41f4-832d-7f1b-bb19-9882365366f5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivables30To59DaysPastDueMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablesPeriodPastDueDomain_019e41f4-832d-7eda-9d3a-c300ccbb11a9" xlink:to="loc_us-gaap_FinancingReceivables30To59DaysPastDueMember_019e41f4-832d-7f1b-bb19-9882365366f5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivables60To89DaysPastDueMember_019e41f4-832d-7bc4-b3cc-cc5b02c74925" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivables60To89DaysPastDueMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablesPeriodPastDueDomain_019e41f4-832d-7eda-9d3a-c300ccbb11a9" xlink:to="loc_us-gaap_FinancingReceivables60To89DaysPastDueMember_019e41f4-832d-7bc4-b3cc-cc5b02c74925" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablesEqualToGreaterThan90DaysPastDueMember_019e41f4-832d-7161-abfe-4fbe09f48708" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivablesEqualToGreaterThan90DaysPastDueMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablesPeriodPastDueDomain_019e41f4-832d-7eda-9d3a-c300ccbb11a9" xlink:to="loc_us-gaap_FinancingReceivablesEqualToGreaterThan90DaysPastDueMember_019e41f4-832d-7161-abfe-4fbe09f48708" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss_019e41f4-832d-7d65-8f7f-aef979b37a0e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentPastDueLineItems_019e41f4-832d-754f-a7a0-94cc21412ad1" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss_019e41f4-832d-7d65-8f7f-aef979b37a0e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing_019e41f4-832d-72dc-958e-90e24efc6e25" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentPastDueLineItems_019e41f4-832d-754f-a7a0-94cc21412ad1" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing_019e41f4-832d-72dc-958e-90e24efc6e25" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.firstmerchants.com/role/LOANSANDALLOWANCEFORCREDITLOSSESSummaryofNonAccrualLoansbyLoanClassDetails" xlink:type="simple" xlink:href="frme-20260630.xsd#LOANSANDALLOWANCEFORCREDITLOSSESSummaryofNonAccrualLoansbyLoanClassDetails"/>
  <link:definitionLink xlink:role="http://www.firstmerchants.com/role/LOANSANDALLOWANCEFORCREDITLOSSESSummaryofNonAccrualLoansbyLoanClassDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentPastDueLineItems_019e41f4-832d-71ce-9098-5cee3aa93b91" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableRecordedInvestmentPastDueLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfFinancingReceivablesPastDueTable_019e41f4-832d-7f0c-9e78-00f277f7b1aa" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfFinancingReceivablesPastDueTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentPastDueLineItems_019e41f4-832d-71ce-9098-5cee3aa93b91" xlink:to="loc_us-gaap_ScheduleOfFinancingReceivablesPastDueTable_019e41f4-832d-7f0c-9e78-00f277f7b1aa" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019e41f4-832d-7987-99ce-f6766d637875" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivablesPastDueTable_019e41f4-832d-7f0c-9e78-00f277f7b1aa" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019e41f4-832d-7987-99ce-f6766d637875" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e41f4-832d-7987-99ce-f6766d637875_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019e41f4-832d-7987-99ce-f6766d637875" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e41f4-832d-7987-99ce-f6766d637875_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e41f4-832d-70cd-b8f7-d55b34db9b5d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019e41f4-832d-7987-99ce-f6766d637875" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e41f4-832d-70cd-b8f7-d55b34db9b5d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_CommercialAndIndustrialLoansMember_019e41f4-832d-74e1-9edc-ebe123263a0d" xlink:href="frme-20260630.xsd#frme_CommercialAndIndustrialLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e41f4-832d-70cd-b8f7-d55b34db9b5d" xlink:to="loc_frme_CommercialAndIndustrialLoansMember_019e41f4-832d-74e1-9edc-ebe123263a0d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_FarmingAndAgricultureMember_019e41f4-832d-7069-ae3b-ce9d1018d661" xlink:href="frme-20260630.xsd#frme_FarmingAndAgricultureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e41f4-832d-70cd-b8f7-d55b34db9b5d" xlink:to="loc_frme_FarmingAndAgricultureMember_019e41f4-832d-7069-ae3b-ce9d1018d661" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConstructionLoansMember_019e41f4-832d-79b5-bb94-ba6bfda1d3a5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConstructionLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e41f4-832d-70cd-b8f7-d55b34db9b5d" xlink:to="loc_us-gaap_ConstructionLoansMember_019e41f4-832d-79b5-bb94-ba6bfda1d3a5" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_CommercialRealEstateNonOwnerOccupiedMember_019e41f4-832d-73e9-9f06-1d7af9dc958f" xlink:href="frme-20260630.xsd#frme_CommercialRealEstateNonOwnerOccupiedMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e41f4-832d-70cd-b8f7-d55b34db9b5d" xlink:to="loc_frme_CommercialRealEstateNonOwnerOccupiedMember_019e41f4-832d-73e9-9f06-1d7af9dc958f" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_CommercialRealEstateOwnerOccupiedMember_019e41f4-832d-79b4-a635-ac3a267354a7" xlink:href="frme-20260630.xsd#frme_CommercialRealEstateOwnerOccupiedMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e41f4-832d-70cd-b8f7-d55b34db9b5d" xlink:to="loc_frme_CommercialRealEstateOwnerOccupiedMember_019e41f4-832d-79b4-a635-ac3a267354a7" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ResidentialRealEstateMember_019e41f4-832d-7022-aa7a-4d51583a818c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ResidentialRealEstateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e41f4-832d-70cd-b8f7-d55b34db9b5d" xlink:to="loc_us-gaap_ResidentialRealEstateMember_019e41f4-832d-7022-aa7a-4d51583a818c" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HomeEquityLoanMember_019e41f4-832d-7bab-993f-ecde21dddd1d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_HomeEquityLoanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e41f4-832d-70cd-b8f7-d55b34db9b5d" xlink:to="loc_us-gaap_HomeEquityLoanMember_019e41f4-832d-7bab-993f-ecde21dddd1d" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConsumerLoanMember_019e41f4-832d-7e57-858e-a812ccd72cf3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConsumerLoanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e41f4-832d-70cd-b8f7-d55b34db9b5d" xlink:to="loc_us-gaap_ConsumerLoanMember_019e41f4-832d-7e57-858e-a812ccd72cf3" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_PublicFinanceAndOtherCommercialLoansMember_019e41f4-832d-70be-83f8-7ef331b29156" xlink:href="frme-20260630.xsd#frme_PublicFinanceAndOtherCommercialLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e41f4-832d-70cd-b8f7-d55b34db9b5d" xlink:to="loc_frme_PublicFinanceAndOtherCommercialLoansMember_019e41f4-832d-70be-83f8-7ef331b29156" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus_019e41f4-832d-7ddf-b76e-d995d8cd51bf" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentPastDueLineItems_019e41f4-832d-71ce-9098-5cee3aa93b91" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus_019e41f4-832d-7ddf-b76e-d995d8cd51bf" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableNonaccrualNoAllowance_019e41f4-832d-71cb-b05d-cac001b6e286" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableNonaccrualNoAllowance"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentPastDueLineItems_019e41f4-832d-71ce-9098-5cee3aa93b91" xlink:to="loc_us-gaap_FinancingReceivableNonaccrualNoAllowance_019e41f4-832d-71cb-b05d-cac001b6e286" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.firstmerchants.com/role/LOANSANDALLOWANCEFORCREDITLOSSESSummaryofAmortizedCostBasisofCollateralDependentLoansDetails" xlink:type="simple" xlink:href="frme-20260630.xsd#LOANSANDALLOWANCEFORCREDITLOSSESSummaryofAmortizedCostBasisofCollateralDependentLoansDetails"/>
  <link:definitionLink xlink:role="http://www.firstmerchants.com/role/LOANSANDALLOWANCEFORCREDITLOSSESSummaryofAmortizedCostBasisofCollateralDependentLoansDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems_019e41f4-832d-75de-91a5-8affdff7d208" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfFinancingReceivableAllowanceForCreditLossesTable_019e41f4-832d-7f44-ac5c-c8f93ca4619b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfFinancingReceivableAllowanceForCreditLossesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems_019e41f4-832d-75de-91a5-8affdff7d208" xlink:to="loc_us-gaap_ScheduleOfFinancingReceivableAllowanceForCreditLossesTable_019e41f4-832d-7f44-ac5c-c8f93ca4619b" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CollateralAxis_019e41f4-832d-7aa7-bab1-7db53d6c43ca" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CollateralAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivableAllowanceForCreditLossesTable_019e41f4-832d-7f44-ac5c-c8f93ca4619b" xlink:to="loc_us-gaap_CollateralAxis_019e41f4-832d-7aa7-bab1-7db53d6c43ca" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CollateralDomain_019e41f4-832d-7aa7-bab1-7db53d6c43ca_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CollateralDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CollateralAxis_019e41f4-832d-7aa7-bab1-7db53d6c43ca" xlink:to="loc_us-gaap_CollateralDomain_019e41f4-832d-7aa7-bab1-7db53d6c43ca_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CollateralDomain_019e41f4-832d-756d-8786-a234ebd57ebe" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CollateralDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CollateralAxis_019e41f4-832d-7aa7-bab1-7db53d6c43ca" xlink:to="loc_us-gaap_CollateralDomain_019e41f4-832d-756d-8786-a234ebd57ebe" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialRealEstateMember_019e41f4-832d-73f3-aa46-05387d5b4b06" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommercialRealEstateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CollateralDomain_019e41f4-832d-756d-8786-a234ebd57ebe" xlink:to="loc_us-gaap_CommercialRealEstateMember_019e41f4-832d-73f3-aa46-05387d5b4b06" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ResidentialRealEstateMember_019e41f4-832d-7d3d-a752-e8896cedfb85" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ResidentialRealEstateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CollateralDomain_019e41f4-832d-756d-8786-a234ebd57ebe" xlink:to="loc_us-gaap_ResidentialRealEstateMember_019e41f4-832d-7d3d-a752-e8896cedfb85" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_BusinessAssetsAndOtherCollateralHeldMember_019e41f4-832d-784d-8db6-15bd32e5d790" xlink:href="frme-20260630.xsd#frme_BusinessAssetsAndOtherCollateralHeldMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CollateralDomain_019e41f4-832d-756d-8786-a234ebd57ebe" xlink:to="loc_frme_BusinessAssetsAndOtherCollateralHeldMember_019e41f4-832d-784d-8db6-15bd32e5d790" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CollateralPledgedMember_019e41f4-832d-7cb8-9bb5-8f35f36c1fb4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CollateralPledgedMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CollateralDomain_019e41f4-832d-756d-8786-a234ebd57ebe" xlink:to="loc_us-gaap_CollateralPledgedMember_019e41f4-832d-7cb8-9bb5-8f35f36c1fb4" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019e41f4-832d-7b04-9f21-4a206ead7e5c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivableAllowanceForCreditLossesTable_019e41f4-832d-7f44-ac5c-c8f93ca4619b" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019e41f4-832d-7b04-9f21-4a206ead7e5c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e41f4-832d-7b04-9f21-4a206ead7e5c_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019e41f4-832d-7b04-9f21-4a206ead7e5c" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e41f4-832d-7b04-9f21-4a206ead7e5c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e41f4-832d-7942-bd5a-f299cb25fc22" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019e41f4-832d-7b04-9f21-4a206ead7e5c" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e41f4-832d-7942-bd5a-f299cb25fc22" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_CommercialAndIndustrialLoansMember_019e41f4-832d-7fe0-ba1f-d03658112c46" xlink:href="frme-20260630.xsd#frme_CommercialAndIndustrialLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e41f4-832d-7942-bd5a-f299cb25fc22" xlink:to="loc_frme_CommercialAndIndustrialLoansMember_019e41f4-832d-7fe0-ba1f-d03658112c46" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConstructionLoansMember_019e41f4-832d-7214-864a-de1886ddcccf" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConstructionLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e41f4-832d-7942-bd5a-f299cb25fc22" xlink:to="loc_us-gaap_ConstructionLoansMember_019e41f4-832d-7214-864a-de1886ddcccf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_CommercialRealEstateNonOwnerOccupiedMember_019e41f4-832d-702b-9ff8-748ddd47c2cd" xlink:href="frme-20260630.xsd#frme_CommercialRealEstateNonOwnerOccupiedMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e41f4-832d-7942-bd5a-f299cb25fc22" xlink:to="loc_frme_CommercialRealEstateNonOwnerOccupiedMember_019e41f4-832d-702b-9ff8-748ddd47c2cd" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_CommercialRealEstateOwnerOccupiedMember_019e41f4-832d-71d2-a69a-56ed11cfb0b9" xlink:href="frme-20260630.xsd#frme_CommercialRealEstateOwnerOccupiedMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e41f4-832d-7942-bd5a-f299cb25fc22" xlink:to="loc_frme_CommercialRealEstateOwnerOccupiedMember_019e41f4-832d-71d2-a69a-56ed11cfb0b9" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealEstateLoanMember_019e41f4-832d-76d5-b0c7-515abd6853af" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RealEstateLoanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e41f4-832d-7942-bd5a-f299cb25fc22" xlink:to="loc_us-gaap_RealEstateLoanMember_019e41f4-832d-76d5-b0c7-515abd6853af" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HomeEquityLoanMember_019e41f4-832d-767d-b6e4-402c3eefae80" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_HomeEquityLoanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e41f4-832d-7942-bd5a-f299cb25fc22" xlink:to="loc_us-gaap_HomeEquityLoanMember_019e41f4-832d-767d-b6e4-402c3eefae80" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableIndividuallyEvaluatedForImpairment_019e41f4-832d-7115-94d6-891f355d81ec" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableIndividuallyEvaluatedForImpairment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems_019e41f4-832d-75de-91a5-8affdff7d208" xlink:to="loc_us-gaap_FinancingReceivableIndividuallyEvaluatedForImpairment_019e41f4-832d-7115-94d6-891f355d81ec" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest_019e41f4-832d-75b2-818a-c70d0e96ae99" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems_019e41f4-832d-75de-91a5-8affdff7d208" xlink:to="loc_us-gaap_FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest_019e41f4-832d-75b2-818a-c70d0e96ae99" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.firstmerchants.com/role/LOANSANDALLOWANCEFORCREDITLOSSESSummaryofTroubledDebtRestructuringsbyModificationTypeDetails" xlink:type="simple" xlink:href="frme-20260630.xsd#LOANSANDALLOWANCEFORCREDITLOSSESSummaryofTroubledDebtRestructuringsbyModificationTypeDetails"/>
  <link:definitionLink xlink:role="http://www.firstmerchants.com/role/LOANSANDALLOWANCEFORCREDITLOSSESSummaryofTroubledDebtRestructuringsbyModificationTypeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_019e41f4-832d-718f-984b-750443dc106b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccountsNotesAndLoansReceivableLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_019e41f4-832d-7481-bc89-387f3b479c9c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_019e41f4-832d-718f-984b-750443dc106b" xlink:to="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_019e41f4-832d-7481-bc89-387f3b479c9c" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019e41f4-832d-752c-abb9-69d963aaa92f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_019e41f4-832d-7481-bc89-387f3b479c9c" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019e41f4-832d-752c-abb9-69d963aaa92f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e41f4-832d-752c-abb9-69d963aaa92f_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019e41f4-832d-752c-abb9-69d963aaa92f" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e41f4-832d-752c-abb9-69d963aaa92f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e41f4-832d-7bb4-a9b1-e66f1b3b1157" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019e41f4-832d-752c-abb9-69d963aaa92f" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e41f4-832d-7bb4-a9b1-e66f1b3b1157" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_CommercialAndIndustrialLoansMember_019e41f4-832d-7ef1-9eaa-90251f2a6dc2" xlink:href="frme-20260630.xsd#frme_CommercialAndIndustrialLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e41f4-832d-7bb4-a9b1-e66f1b3b1157" xlink:to="loc_frme_CommercialAndIndustrialLoansMember_019e41f4-832d-7ef1-9eaa-90251f2a6dc2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConstructionLoansMember_019e41f4-832d-7b18-a28f-aa1583b99e43" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConstructionLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e41f4-832d-7bb4-a9b1-e66f1b3b1157" xlink:to="loc_us-gaap_ConstructionLoansMember_019e41f4-832d-7b18-a28f-aa1583b99e43" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_CommercialRealEstateNonOwnerOccupiedMember_019e41f4-832d-76b2-bc7f-9892b973d0b0" xlink:href="frme-20260630.xsd#frme_CommercialRealEstateNonOwnerOccupiedMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e41f4-832d-7bb4-a9b1-e66f1b3b1157" xlink:to="loc_frme_CommercialRealEstateNonOwnerOccupiedMember_019e41f4-832d-76b2-bc7f-9892b973d0b0" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_CommercialRealEstateOwnerOccupiedMember_019e41f4-832d-7a8f-a265-04f1376c6276" xlink:href="frme-20260630.xsd#frme_CommercialRealEstateOwnerOccupiedMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e41f4-832d-7bb4-a9b1-e66f1b3b1157" xlink:to="loc_frme_CommercialRealEstateOwnerOccupiedMember_019e41f4-832d-7a8f-a265-04f1376c6276" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ResidentialRealEstateMember_019e41f4-832d-762a-bf1b-43a96f3d4390" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ResidentialRealEstateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e41f4-832d-7bb4-a9b1-e66f1b3b1157" xlink:to="loc_us-gaap_ResidentialRealEstateMember_019e41f4-832d-762a-bf1b-43a96f3d4390" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HomeEquityLoanMember_019e509d-44cb-7a4b-be4b-27e10e5980f6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_HomeEquityLoanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e41f4-832d-7bb4-a9b1-e66f1b3b1157" xlink:to="loc_us-gaap_HomeEquityLoanMember_019e509d-44cb-7a4b-be4b-27e10e5980f6" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LoanRestructuringModificationAxis_019e41f4-832d-7389-90cc-14ebad8343e9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LoanRestructuringModificationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_019e41f4-832d-7481-bc89-387f3b479c9c" xlink:to="loc_us-gaap_LoanRestructuringModificationAxis_019e41f4-832d-7389-90cc-14ebad8343e9" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LoanRestructuringModificationDomain_019e41f4-832d-7389-90cc-14ebad8343e9_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LoanRestructuringModificationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LoanRestructuringModificationAxis_019e41f4-832d-7389-90cc-14ebad8343e9" xlink:to="loc_us-gaap_LoanRestructuringModificationDomain_019e41f4-832d-7389-90cc-14ebad8343e9_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LoanRestructuringModificationDomain_019e41f4-832d-70cc-9881-1b4cf3d89554" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LoanRestructuringModificationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LoanRestructuringModificationAxis_019e41f4-832d-7389-90cc-14ebad8343e9" xlink:to="loc_us-gaap_LoanRestructuringModificationDomain_019e41f4-832d-70cc-9881-1b4cf3d89554" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ExtendedMaturityMember_019e41f4-832d-742b-a505-6fbb1bf82210" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ExtendedMaturityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LoanRestructuringModificationDomain_019e41f4-832d-70cc-9881-1b4cf3d89554" xlink:to="loc_us-gaap_ExtendedMaturityMember_019e41f4-832d-742b-a505-6fbb1bf82210" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_PaymentDeferralAndExtendedMaturityMember_019e41f4-832d-7339-a4b0-2062c89f7fe5" xlink:href="frme-20260630.xsd#frme_PaymentDeferralAndExtendedMaturityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LoanRestructuringModificationDomain_019e41f4-832d-70cc-9881-1b4cf3d89554" xlink:to="loc_frme_PaymentDeferralAndExtendedMaturityMember_019e41f4-832d-7339-a4b0-2062c89f7fe5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentDeferralMember_019e41f4-832d-70f5-806c-018b625630b7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PaymentDeferralMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LoanRestructuringModificationDomain_019e41f4-832d-70cc-9881-1b4cf3d89554" xlink:to="loc_us-gaap_PaymentDeferralMember_019e41f4-832d-70f5-806c-018b625630b7" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractualInterestRateReductionMember_019e4f99-b39a-7dab-a948-584c1d875915" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ContractualInterestRateReductionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LoanRestructuringModificationDomain_019e41f4-832d-70cc-9881-1b4cf3d89554" xlink:to="loc_us-gaap_ContractualInterestRateReductionMember_019e4f99-b39a-7dab-a948-584c1d875915" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ExtendedMaturityAndInterestRateReductionMember_019e41f4-832d-73f7-9c8c-d775a871696c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ExtendedMaturityAndInterestRateReductionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LoanRestructuringModificationDomain_019e41f4-832d-70cc-9881-1b4cf3d89554" xlink:to="loc_us-gaap_ExtendedMaturityAndInterestRateReductionMember_019e41f4-832d-73f7-9c8c-d775a871696c" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_InterestRateReductionExtendedMaturityAndPaymentDeferralMember_019e41f4-832d-7175-87b6-a7b153af46f2" xlink:href="frme-20260630.xsd#frme_InterestRateReductionExtendedMaturityAndPaymentDeferralMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LoanRestructuringModificationDomain_019e41f4-832d-70cc-9881-1b4cf3d89554" xlink:to="loc_frme_InterestRateReductionExtendedMaturityAndPaymentDeferralMember_019e41f4-832d-7175-87b6-a7b153af46f2" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_019fa987-44f0-70c3-8666-998df8c06b4a" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_019e41f4-832d-7481-bc89-387f3b479c9c" xlink:to="loc_srt_RangeAxis_019fa987-44f0-70c3-8666-998df8c06b4a" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_019fa987-44f0-70c3-8666-998df8c06b4a_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_019fa987-44f0-70c3-8666-998df8c06b4a" xlink:to="loc_srt_RangeMember_019fa987-44f0-70c3-8666-998df8c06b4a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_019fa987-44f0-7743-bd34-4c9911254610" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_019fa987-44f0-70c3-8666-998df8c06b4a" xlink:to="loc_srt_RangeMember_019fa987-44f0-7743-bd34-4c9911254610" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_WeightedAverageMember_019fa987-66fa-74da-955b-9c2c29f4c8f1" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_WeightedAverageMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_019fa987-44f0-7743-bd34-4c9911254610" xlink:to="loc_srt_WeightedAverageMember_019fa987-66fa-74da-955b-9c2c29f4c8f1" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestModifiedPeriod_019e41f4-832d-705b-80e3-695a0c8284d6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestModifiedPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_019e41f4-832d-718f-984b-750443dc106b" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestModifiedPeriod_019e41f4-832d-705b-80e3-695a0c8284d6" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableModificationToTotalFinancingReceivablesExcludingAccruedInterestPercent_019e41f4-832d-79e3-a86f-7a129f307b88" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableModificationToTotalFinancingReceivablesExcludingAccruedInterestPercent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_019e41f4-832d-718f-984b-750443dc106b" xlink:to="loc_us-gaap_FinancingReceivableModificationToTotalFinancingReceivablesExcludingAccruedInterestPercent_019e41f4-832d-79e3-a86f-7a129f307b88" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableModifiedWeightedAverageTermIncreaseFromModification_019e41f4-832d-72fc-a05e-e841029cb802" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableModifiedWeightedAverageTermIncreaseFromModification"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_019e41f4-832d-718f-984b-750443dc106b" xlink:to="loc_us-gaap_FinancingReceivableModifiedWeightedAverageTermIncreaseFromModification_019e41f4-832d-72fc-a05e-e841029cb802" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2_019e41f4-832d-728c-bc97-0e30a45cc2e9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_019e41f4-832d-718f-984b-750443dc106b" xlink:to="loc_us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2_019e41f4-832d-728c-bc97-0e30a45cc2e9" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableModifiedWeightedAverageInterestRateBeforeModification_019e41f4-832d-7306-baf7-d5f290ec216b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableModifiedWeightedAverageInterestRateBeforeModification"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_019e41f4-832d-718f-984b-750443dc106b" xlink:to="loc_us-gaap_FinancingReceivableModifiedWeightedAverageInterestRateBeforeModification_019e41f4-832d-7306-baf7-d5f290ec216b" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableModifiedWeightedAverageInterestRateAfterModification_019e41f4-832d-7d09-b06b-7597569ac9a1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableModifiedWeightedAverageInterestRateAfterModification"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_019e41f4-832d-718f-984b-750443dc106b" xlink:to="loc_us-gaap_FinancingReceivableModifiedWeightedAverageInterestRateAfterModification_019e41f4-832d-7d09-b06b-7597569ac9a1" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_FinancingReceivableModifiedDuringThePeriodWeightedAverageInterestRateBeforeModification_019e4fad-4c04-71eb-9ffb-8d278820805b" xlink:href="frme-20260630.xsd#frme_FinancingReceivableModifiedDuringThePeriodWeightedAverageInterestRateBeforeModification"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_019e41f4-832d-718f-984b-750443dc106b" xlink:to="loc_frme_FinancingReceivableModifiedDuringThePeriodWeightedAverageInterestRateBeforeModification_019e4fad-4c04-71eb-9ffb-8d278820805b" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_FinancingReceivableModifiedDuringThePeriodWeightedAverageInterestRateAfterModification_019e4fad-b04d-7baa-b976-b3ed04c7a895" xlink:href="frme-20260630.xsd#frme_FinancingReceivableModifiedDuringThePeriodWeightedAverageInterestRateAfterModification"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_019e41f4-832d-718f-984b-750443dc106b" xlink:to="loc_frme_FinancingReceivableModifiedDuringThePeriodWeightedAverageInterestRateAfterModification_019e4fad-b04d-7baa-b976-b3ed04c7a895" xlink:type="arc" order="7"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.firstmerchants.com/role/LOANSANDALLOWANCEFORCREDITLOSSESSummaryofPaymentStatusDetails" xlink:type="simple" xlink:href="frme-20260630.xsd#LOANSANDALLOWANCEFORCREDITLOSSESSummaryofPaymentStatusDetails"/>
  <link:definitionLink xlink:role="http://www.firstmerchants.com/role/LOANSANDALLOWANCEFORCREDITLOSSESSummaryofPaymentStatusDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableModificationsLineItems_019e41f4-832d-77df-b365-4574511a24b0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableModificationsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfFinancingReceivableTroubledDebtRestructuringsTable_019e41f4-832d-7734-b136-9d311e011cd9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfFinancingReceivableTroubledDebtRestructuringsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FinancingReceivableModificationsLineItems_019e41f4-832d-77df-b365-4574511a24b0" xlink:to="loc_us-gaap_ScheduleOfFinancingReceivableTroubledDebtRestructuringsTable_019e41f4-832d-7734-b136-9d311e011cd9" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019e41f4-832d-767f-80b1-c151b8544191" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivableTroubledDebtRestructuringsTable_019e41f4-832d-7734-b136-9d311e011cd9" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019e41f4-832d-767f-80b1-c151b8544191" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e41f4-832d-767f-80b1-c151b8544191_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019e41f4-832d-767f-80b1-c151b8544191" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e41f4-832d-767f-80b1-c151b8544191_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e41f4-832d-74d2-81a7-18065cd75c30" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019e41f4-832d-767f-80b1-c151b8544191" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e41f4-832d-74d2-81a7-18065cd75c30" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_CommercialAndIndustrialLoansMember_019e41f4-832d-7257-85cc-77fd7081deae" xlink:href="frme-20260630.xsd#frme_CommercialAndIndustrialLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e41f4-832d-74d2-81a7-18065cd75c30" xlink:to="loc_frme_CommercialAndIndustrialLoansMember_019e41f4-832d-7257-85cc-77fd7081deae" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_FarmingAndAgricultureMember_019e41f4-832d-756f-a39d-f84793acddfa" xlink:href="frme-20260630.xsd#frme_FarmingAndAgricultureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e41f4-832d-74d2-81a7-18065cd75c30" xlink:to="loc_frme_FarmingAndAgricultureMember_019e41f4-832d-756f-a39d-f84793acddfa" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConstructionLoansMember_019e41f4-832d-7c22-acad-d73c8eb2d867" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConstructionLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e41f4-832d-74d2-81a7-18065cd75c30" xlink:to="loc_us-gaap_ConstructionLoansMember_019e41f4-832d-7c22-acad-d73c8eb2d867" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_CommercialRealEstateNonOwnerOccupiedMember_019e41f4-832d-7b31-b6bd-1c990ae47f43" xlink:href="frme-20260630.xsd#frme_CommercialRealEstateNonOwnerOccupiedMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e41f4-832d-74d2-81a7-18065cd75c30" xlink:to="loc_frme_CommercialRealEstateNonOwnerOccupiedMember_019e41f4-832d-7b31-b6bd-1c990ae47f43" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_CommercialRealEstateOwnerOccupiedMember_019e41f4-832d-71d8-ae63-5dc796a8c377" xlink:href="frme-20260630.xsd#frme_CommercialRealEstateOwnerOccupiedMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e41f4-832d-74d2-81a7-18065cd75c30" xlink:to="loc_frme_CommercialRealEstateOwnerOccupiedMember_019e41f4-832d-71d8-ae63-5dc796a8c377" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ResidentialRealEstateMember_019e41f4-832d-70e7-86a7-2ed1d860943a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ResidentialRealEstateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e41f4-832d-74d2-81a7-18065cd75c30" xlink:to="loc_us-gaap_ResidentialRealEstateMember_019e41f4-832d-70e7-86a7-2ed1d860943a" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HomeEquityLoanMember_019e41f4-832d-77a9-a10f-029b602af354" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_HomeEquityLoanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019e41f4-832d-74d2-81a7-18065cd75c30" xlink:to="loc_us-gaap_HomeEquityLoanMember_019e41f4-832d-77a9-a10f-029b602af354" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablesPeriodPastDueAxis_019e41f4-832d-7e4b-a5d1-208c6b85a6f2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivablesPeriodPastDueAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivableTroubledDebtRestructuringsTable_019e41f4-832d-7734-b136-9d311e011cd9" xlink:to="loc_us-gaap_FinancingReceivablesPeriodPastDueAxis_019e41f4-832d-7e4b-a5d1-208c6b85a6f2" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablesPeriodPastDueDomain_019e41f4-832d-7e4b-a5d1-208c6b85a6f2_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivablesPeriodPastDueDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivablesPeriodPastDueAxis_019e41f4-832d-7e4b-a5d1-208c6b85a6f2" xlink:to="loc_us-gaap_FinancingReceivablesPeriodPastDueDomain_019e41f4-832d-7e4b-a5d1-208c6b85a6f2_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablesPeriodPastDueDomain_019e41f4-832d-7bb5-b8a9-106e9244f3b3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivablesPeriodPastDueDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivablesPeriodPastDueAxis_019e41f4-832d-7e4b-a5d1-208c6b85a6f2" xlink:to="loc_us-gaap_FinancingReceivablesPeriodPastDueDomain_019e41f4-832d-7bb5-b8a9-106e9244f3b3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialAssetNotPastDueMember_019e41f4-832d-7cd9-b16b-4285f898598d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancialAssetNotPastDueMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablesPeriodPastDueDomain_019e41f4-832d-7bb5-b8a9-106e9244f3b3" xlink:to="loc_us-gaap_FinancialAssetNotPastDueMember_019e41f4-832d-7cd9-b16b-4285f898598d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivables30To59DaysPastDueMember_019e41f4-832d-7f59-8b04-ce1469ad3396" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivables30To59DaysPastDueMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablesPeriodPastDueDomain_019e41f4-832d-7bb5-b8a9-106e9244f3b3" xlink:to="loc_us-gaap_FinancingReceivables30To59DaysPastDueMember_019e41f4-832d-7f59-8b04-ce1469ad3396" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivables60To89DaysPastDueMember_019e41f4-832d-7945-a5d7-c460bda52da5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivables60To89DaysPastDueMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablesPeriodPastDueDomain_019e41f4-832d-7bb5-b8a9-106e9244f3b3" xlink:to="loc_us-gaap_FinancingReceivables60To89DaysPastDueMember_019e41f4-832d-7945-a5d7-c460bda52da5" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablesEqualToGreaterThan90DaysPastDueMember_019e41f4-832d-7b42-b52b-4e6c85faf7bf" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivablesEqualToGreaterThan90DaysPastDueMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablesPeriodPastDueDomain_019e41f4-832d-7bb5-b8a9-106e9244f3b3" xlink:to="loc_us-gaap_FinancingReceivablesEqualToGreaterThan90DaysPastDueMember_019e41f4-832d-7b42-b52b-4e6c85faf7bf" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestModifiedPeriod_019e41f4-832d-79c6-b85e-5c3adbc306cb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestModifiedPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableModificationsLineItems_019e41f4-832d-77df-b365-4574511a24b0" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestModifiedPeriod_019e41f4-832d-79c6-b85e-5c3adbc306cb" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.firstmerchants.com/role/LOANSANDALLOWANCEFORCREDITLOSSESSummaryofChangesinAllowanceforLoanLossesbyLoanSegmentDetails" xlink:type="simple" xlink:href="frme-20260630.xsd#LOANSANDALLOWANCEFORCREDITLOSSESSummaryofChangesinAllowanceforLoanLossesbyLoanSegmentDetails"/>
  <link:definitionLink xlink:role="http://www.firstmerchants.com/role/LOANSANDALLOWANCEFORCREDITLOSSESSummaryofChangesinAllowanceforLoanLossesbyLoanSegmentDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems_019e41f4-832d-78d0-a461-9f4eee914e84" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfFinancingReceivableAllowanceForCreditLossesTable_019e41f4-832d-7edd-9b31-72a5bdf0c186" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfFinancingReceivableAllowanceForCreditLossesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems_019e41f4-832d-78d0-a461-9f4eee914e84" xlink:to="loc_us-gaap_ScheduleOfFinancingReceivableAllowanceForCreditLossesTable_019e41f4-832d-7edd-9b31-72a5bdf0c186" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_019e41f4-832d-77a8-bd0b-d23f9a461ca1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivablePortfolioSegmentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivableAllowanceForCreditLossesTable_019e41f4-832d-7edd-9b31-72a5bdf0c186" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_019e41f4-832d-77a8-bd0b-d23f9a461ca1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019e41f4-832d-77a8-bd0b-d23f9a461ca1_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_019e41f4-832d-77a8-bd0b-d23f9a461ca1" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019e41f4-832d-77a8-bd0b-d23f9a461ca1_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019e41f4-832d-7f99-bc98-cf05e590539e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_019e41f4-832d-77a8-bd0b-d23f9a461ca1" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019e41f4-832d-7f99-bc98-cf05e590539e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialPortfolioSegmentMember_019e41f4-832d-7d68-9f70-7342e2e1fd34" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommercialPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019e41f4-832d-7f99-bc98-cf05e590539e" xlink:to="loc_us-gaap_CommercialPortfolioSegmentMember_019e41f4-832d-7d68-9f70-7342e2e1fd34" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialRealEstatePortfolioSegmentMember_019e41f4-832d-76b8-822a-8ad39c0ca312" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommercialRealEstatePortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019e41f4-832d-7f99-bc98-cf05e590539e" xlink:to="loc_us-gaap_CommercialRealEstatePortfolioSegmentMember_019e41f4-832d-76b8-822a-8ad39c0ca312" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_ConstructionPortfolioSegmentMember_019e41f4-832d-735b-af5a-929722886907" xlink:href="frme-20260630.xsd#frme_ConstructionPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019e41f4-832d-7f99-bc98-cf05e590539e" xlink:to="loc_frme_ConstructionPortfolioSegmentMember_019e41f4-832d-735b-af5a-929722886907" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_ConsumerAndResidentialPortfolioSegmentMember_019e41f4-832d-7731-b3e1-c4b3f50a3131" xlink:href="frme-20260630.xsd#frme_ConsumerAndResidentialPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019e41f4-832d-7f99-bc98-cf05e590539e" xlink:to="loc_frme_ConsumerAndResidentialPortfolioSegmentMember_019e41f4-832d-7731-b3e1-c4b3f50a3131" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesRollForward_019e41f4-832d-79cb-8a73-2a32f50115eb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableAllowanceForCreditLossesRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems_019e41f4-832d-78d0-a461-9f4eee914e84" xlink:to="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesRollForward_019e41f4-832d-79cb-8a73-2a32f50115eb" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest_019e41f4-832d-7133-9a74-204462be5e22" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesRollForward_019e41f4-832d-79cb-8a73-2a32f50115eb" xlink:to="loc_us-gaap_FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest_019e41f4-832d-7133-9a74-204462be5e22" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProvisionForLoanLossesExpensed_019e41f4-832d-743e-aae6-a23c05672bed" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProvisionForLoanLossesExpensed"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesRollForward_019e41f4-832d-79cb-8a73-2a32f50115eb" xlink:to="loc_us-gaap_ProvisionForLoanLossesExpensed_019e41f4-832d-743e-aae6-a23c05672bed" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossLoanPurchased_019e41f4-832d-7c4e-b2fc-b0c107ca399b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossLoanPurchased"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesRollForward_019e41f4-832d-79cb-8a73-2a32f50115eb" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossLoanPurchased_019e41f4-832d-7c4e-b2fc-b0c107ca399b" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableAllowanceForCreditLossPurchasedWithCreditDeteriorationIncrease_019e41f4-832d-7ead-a11f-fd7e59b7b378" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableAllowanceForCreditLossPurchasedWithCreditDeteriorationIncrease"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesRollForward_019e41f4-832d-79cb-8a73-2a32f50115eb" xlink:to="loc_us-gaap_FinancingReceivableAllowanceForCreditLossPurchasedWithCreditDeteriorationIncrease_019e41f4-832d-7ead-a11f-fd7e59b7b378" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesRecovery_019e41f4-832d-70cf-9cda-7f9905dd968a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableAllowanceForCreditLossesRecovery"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesRollForward_019e41f4-832d-79cb-8a73-2a32f50115eb" xlink:to="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesRecovery_019e41f4-832d-70cf-9cda-7f9905dd968a" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesWriteOffs_019e41f4-832d-7322-8110-303dafd50bd1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableAllowanceForCreditLossesWriteOffs"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesRollForward_019e41f4-832d-79cb-8a73-2a32f50115eb" xlink:to="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesWriteOffs_019e41f4-832d-7322-8110-303dafd50bd1" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest_019e41f4-832d-7d78-9fc4-0ca674c52495" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.firstmerchants.com/role/LOANSANDALLOWANCEFORCREDITLOSSESSummaryofAmountsofCommitmentsDetails" xlink:type="simple" xlink:href="frme-20260630.xsd#LOANSANDALLOWANCEFORCREDITLOSSESSummaryofAmountsofCommitmentsDetails"/>
  <link:definitionLink xlink:role="http://www.firstmerchants.com/role/LOANSANDALLOWANCEFORCREDITLOSSESSummaryofAmountsofCommitmentsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueOffBalanceSheetRisksDisclosureInformationLineItems_019e41f4-832d-7c87-9999-c6b4a6a82e16" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueOffBalanceSheetRisksDisclosureInformationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfFairValueOffBalanceSheetRisksTable_019e41f4-832d-7012-8c47-046b24e909c1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfFairValueOffBalanceSheetRisksTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueOffBalanceSheetRisksDisclosureInformationLineItems_019e41f4-832d-7c87-9999-c6b4a6a82e16" xlink:to="loc_us-gaap_ScheduleOfFairValueOffBalanceSheetRisksTable_019e41f4-832d-7012-8c47-046b24e909c1" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentAxis_019e41f4-832d-7d75-adb5-dc3cdaf9007d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancialInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFairValueOffBalanceSheetRisksTable_019e41f4-832d-7012-8c47-046b24e909c1" xlink:to="loc_us-gaap_FinancialInstrumentAxis_019e41f4-832d-7d75-adb5-dc3cdaf9007d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e41f4-832d-7d75-adb5-dc3cdaf9007d_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentAxis_019e41f4-832d-7d75-adb5-dc3cdaf9007d" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e41f4-832d-7d75-adb5-dc3cdaf9007d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e41f4-832d-775d-b8fc-91e0ea7a2bd1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentAxis_019e41f4-832d-7d75-adb5-dc3cdaf9007d" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e41f4-832d-775d-b8fc-91e0ea7a2bd1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommitmentsToExtendCreditMember_019e41f4-832d-7bb4-bbe4-e85f8e9d85fd" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommitmentsToExtendCreditMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e41f4-832d-775d-b8fc-91e0ea7a2bd1" xlink:to="loc_us-gaap_CommitmentsToExtendCreditMember_019e41f4-832d-7bb4-bbe4-e85f8e9d85fd" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StandbyLettersOfCreditMember_019e41f4-832d-75e8-ab8e-1d532c5ede07" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StandbyLettersOfCreditMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e41f4-832d-775d-b8fc-91e0ea7a2bd1" xlink:to="loc_us-gaap_StandbyLettersOfCreditMember_019e41f4-832d-75e8-ab8e-1d532c5ede07" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueDisclosureOffbalanceSheetRisksAmountLiability_019e41f4-832d-7f00-b932-a4650884c2af" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueDisclosureOffbalanceSheetRisksAmountLiability"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueOffBalanceSheetRisksDisclosureInformationLineItems_019e41f4-832d-7c87-9999-c6b4a6a82e16" xlink:to="loc_us-gaap_FairValueDisclosureOffbalanceSheetRisksAmountLiability_019e41f4-832d-7f00-b932-a4650884c2af" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.firstmerchants.com/role/GOODWILLANDOTHERINTANGIBLESNarrativeDetails" xlink:type="simple" xlink:href="frme-20260630.xsd#GOODWILLANDOTHERINTANGIBLESNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.firstmerchants.com/role/GOODWILLANDOTHERINTANGIBLESNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillLineItems_019e41f4-832d-7c0c-a778-25b7a054834e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_GoodwillLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfGoodwillTable_019e41f4-832d-7510-8717-6897b59742c9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfGoodwillTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_GoodwillLineItems_019e41f4-832d-7c0c-a778-25b7a054834e" xlink:to="loc_us-gaap_ScheduleOfGoodwillTable_019e41f4-832d-7510-8717-6897b59742c9" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_019e41f4-832d-7eda-a707-4d6f37a42802" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessAcquisitionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfGoodwillTable_019e41f4-832d-7510-8717-6897b59742c9" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_019e41f4-832d-7eda-a707-4d6f37a42802" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_019e41f4-832d-7eda-a707-4d6f37a42802_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_019e41f4-832d-7eda-a707-4d6f37a42802" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_019e41f4-832d-7eda-a707-4d6f37a42802_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_019e41f4-832d-79e0-8708-e4d0cfb869d3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_019e41f4-832d-7eda-a707-4d6f37a42802" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_019e41f4-832d-79e0-8708-e4d0cfb869d3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_FirstSavingsFinancialGroupInc.Member_019e41f4-832d-7f81-ad7e-253ab3bef761" xlink:href="frme-20260630.xsd#frme_FirstSavingsFinancialGroupInc.Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_019e41f4-832d-79e0-8708-e4d0cfb869d3" xlink:to="loc_frme_FirstSavingsFinancialGroupInc.Member_019e41f4-832d-7f81-ad7e-253ab3bef761" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_019e41f4-832d-7ea2-8caf-0602a7da9c26" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfGoodwillTable_019e41f4-832d-7510-8717-6897b59742c9" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_019e41f4-832d-7ea2-8caf-0602a7da9c26" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_019e41f4-832d-7ea2-8caf-0602a7da9c26_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_019e41f4-832d-7ea2-8caf-0602a7da9c26" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_019e41f4-832d-7ea2-8caf-0602a7da9c26_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_019e41f4-832d-7368-b0ea-54f6e48cfca4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_019e41f4-832d-7ea2-8caf-0602a7da9c26" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_019e41f4-832d-7368-b0ea-54f6e48cfca4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CoreDepositsMember_019e41f4-832d-7e5e-8ad9-4e313a91d3e6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CoreDepositsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_019e41f4-832d-7368-b0ea-54f6e48cfca4" xlink:to="loc_us-gaap_CoreDepositsMember_019e41f4-832d-7e5e-8ad9-4e313a91d3e6" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherIntangibleAssetsMember_019e41f4-832d-713f-95b8-3919e6fd786f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherIntangibleAssetsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_019e41f4-832d-7368-b0ea-54f6e48cfca4" xlink:to="loc_us-gaap_OtherIntangibleAssetsMember_019e41f4-832d-713f-95b8-3919e6fd786f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_019e41f4-832d-738d-80b2-577763d5e05d" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfGoodwillTable_019e41f4-832d-7510-8717-6897b59742c9" xlink:to="loc_srt_RangeAxis_019e41f4-832d-738d-80b2-577763d5e05d" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_019e41f4-832d-738d-80b2-577763d5e05d_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_019e41f4-832d-738d-80b2-577763d5e05d" xlink:to="loc_srt_RangeMember_019e41f4-832d-738d-80b2-577763d5e05d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_019e41f4-832d-7854-9c10-d275622b1f5f" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_019e41f4-832d-738d-80b2-577763d5e05d" xlink:to="loc_srt_RangeMember_019e41f4-832d-7854-9c10-d275622b1f5f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_019e41f4-832d-71e6-a049-177c45259641" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_019e41f4-832d-7854-9c10-d275622b1f5f" xlink:to="loc_srt_MinimumMember_019e41f4-832d-71e6-a049-177c45259641" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_019e41f4-832d-745a-8f55-3b70ba24867d" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_019e41f4-832d-7854-9c10-d275622b1f5f" xlink:to="loc_srt_MaximumMember_019e41f4-832d-745a-8f55-3b70ba24867d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Goodwill_019e41f4-832d-7fd7-a4a7-b2ca110ffb78" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_Goodwill"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GoodwillLineItems_019e41f4-832d-7c0c-a778-25b7a054834e" xlink:to="loc_us-gaap_Goodwill_019e41f4-832d-7fd7-a4a7-b2ca110ffb78" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinitelivedIntangibleAssetsAcquired1_019e41f4-832d-7614-94b0-86f891b77256" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinitelivedIntangibleAssetsAcquired1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GoodwillLineItems_019e41f4-832d-7c0c-a778-25b7a054834e" xlink:to="loc_us-gaap_FinitelivedIntangibleAssetsAcquired1_019e41f4-832d-7614-94b0-86f891b77256" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetUsefulLife_019e41f4-832d-7145-a6f2-c17a38e3ee23" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FiniteLivedIntangibleAssetUsefulLife"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GoodwillLineItems_019e41f4-832d-7c0c-a778-25b7a054834e" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetUsefulLife_019e41f4-832d-7145-a6f2-c17a38e3ee23" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AmortizationOfIntangibleAssets_019e41f4-832d-7ac7-af66-95c54bcbff00" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AmortizationOfIntangibleAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GoodwillLineItems_019e41f4-832d-7c0c-a778-25b7a054834e" xlink:to="loc_us-gaap_AmortizationOfIntangibleAssets_019e41f4-832d-7ac7-af66-95c54bcbff00" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.firstmerchants.com/role/DERIVATIVEFINANCIALINSTRUMENTSSummaryofFairValueofDerivativeFinancialInstrumentsandClassificationontheBalanceSheetDetails" xlink:type="simple" xlink:href="frme-20260630.xsd#DERIVATIVEFINANCIALINSTRUMENTSSummaryofFairValueofDerivativeFinancialInstrumentsandClassificationontheBalanceSheetDetails"/>
  <link:definitionLink xlink:role="http://www.firstmerchants.com/role/DERIVATIVEFINANCIALINSTRUMENTSSummaryofFairValueofDerivativeFinancialInstrumentsandClassificationontheBalanceSheetDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativesFairValueLineItems_019e41f4-832d-7c0e-ac9d-888e18d61c2e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativesFairValueLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_019e41f4-832d-7abf-a0bf-f28bbd5535e8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DerivativesFairValueLineItems_019e41f4-832d-7c0e-ac9d-888e18d61c2e" xlink:to="loc_us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_019e41f4-832d-7abf-a0bf-f28bbd5535e8" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationAxis_019e41f4-832d-715b-8cf6-fefd01f06fbd" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_HedgingDesignationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_019e41f4-832d-7abf-a0bf-f28bbd5535e8" xlink:to="loc_us-gaap_HedgingDesignationAxis_019e41f4-832d-715b-8cf6-fefd01f06fbd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationDomain_019e41f4-832d-715b-8cf6-fefd01f06fbd_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_HedgingDesignationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_HedgingDesignationAxis_019e41f4-832d-715b-8cf6-fefd01f06fbd" xlink:to="loc_us-gaap_HedgingDesignationDomain_019e41f4-832d-715b-8cf6-fefd01f06fbd_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationDomain_019e41f4-832d-7a90-846f-856139591339" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_HedgingDesignationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_HedgingDesignationAxis_019e41f4-832d-715b-8cf6-fefd01f06fbd" xlink:to="loc_us-gaap_HedgingDesignationDomain_019e41f4-832d-7a90-846f-856139591339" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NondesignatedMember_019e41f4-832d-7b39-b2a1-8489be4f13c1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NondesignatedMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HedgingDesignationDomain_019e41f4-832d-7a90-846f-856139591339" xlink:to="loc_us-gaap_NondesignatedMember_019e41f4-832d-7b39-b2a1-8489be4f13c1" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_019e41f4-832d-73ec-98a6-9d674724c6bb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeInstrumentRiskAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_019e41f4-832d-7abf-a0bf-f28bbd5535e8" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_019e41f4-832d-73ec-98a6-9d674724c6bb" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_019e41f4-832d-73ec-98a6-9d674724c6bb_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_019e41f4-832d-73ec-98a6-9d674724c6bb" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_019e41f4-832d-73ec-98a6-9d674724c6bb_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_019e41f4-832d-7c4e-8f93-9457e3e10f40" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_019e41f4-832d-73ec-98a6-9d674724c6bb" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_019e41f4-832d-7c4e-8f93-9457e3e10f40" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestRateSwapMember_019e41f4-832d-70f5-b4da-493fd3a7ae21" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestRateSwapMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_019e41f4-832d-7c4e-8f93-9457e3e10f40" xlink:to="loc_us-gaap_InterestRateSwapMember_019e41f4-832d-70f5-b4da-493fd3a7ae21" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ForwardContractsMember_019e41f4-832d-7ee4-9b97-838122c678e6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ForwardContractsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_019e41f4-832d-7c4e-8f93-9457e3e10f40" xlink:to="loc_us-gaap_ForwardContractsMember_019e41f4-832d-7ee4-9b97-838122c678e6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestRateLockCommitmentsMember_019e41f4-832d-7014-98ba-e0ef8b3c003a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestRateLockCommitmentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_019e41f4-832d-7c4e-8f93-9457e3e10f40" xlink:to="loc_us-gaap_InterestRateLockCommitmentsMember_019e41f4-832d-7014-98ba-e0ef8b3c003a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NotionalAmountOfDerivativesAbstract_019e41f4-832d-75f0-a4a5-1f620bf4ec71" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NotionalAmountOfDerivativesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativesFairValueLineItems_019e41f4-832d-7c0e-ac9d-888e18d61c2e" xlink:to="loc_us-gaap_NotionalAmountOfDerivativesAbstract_019e41f4-832d-75f0-a4a5-1f620bf4ec71" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeAssetNotionalAmount_019e41f4-832d-7afc-bd7f-fcf9d25c6497" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeAssetNotionalAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NotionalAmountOfDerivativesAbstract_019e41f4-832d-75f0-a4a5-1f620bf4ec71" xlink:to="loc_us-gaap_DerivativeAssetNotionalAmount_019e41f4-832d-7afc-bd7f-fcf9d25c6497" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeLiabilityNotionalAmount_019e41f4-832d-773b-a82e-d74dc14f756b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeLiabilityNotionalAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NotionalAmountOfDerivativesAbstract_019e41f4-832d-75f0-a4a5-1f620bf4ec71" xlink:to="loc_us-gaap_DerivativeLiabilityNotionalAmount_019e41f4-832d-773b-a82e-d74dc14f756b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeFairValueOfDerivativeNetAbstract_019e41f4-832d-7ad0-8705-b5f34a3baf09" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeFairValueOfDerivativeNetAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativesFairValueLineItems_019e41f4-832d-7c0e-ac9d-888e18d61c2e" xlink:to="loc_us-gaap_DerivativeFairValueOfDerivativeNetAbstract_019e41f4-832d-7ad0-8705-b5f34a3baf09" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeFairValueOfDerivativeAsset_019e41f4-832d-7c42-b53e-7b959d81d2e9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeFairValueOfDerivativeAsset"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeFairValueOfDerivativeNetAbstract_019e41f4-832d-7ad0-8705-b5f34a3baf09" xlink:to="loc_us-gaap_DerivativeFairValueOfDerivativeAsset_019e41f4-832d-7c42-b53e-7b959d81d2e9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeFairValueOfDerivativeLiability_019e41f4-832d-762f-85db-39afe5ed3819" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeFairValueOfDerivativeLiability"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeFairValueOfDerivativeNetAbstract_019e41f4-832d-7ad0-8705-b5f34a3baf09" xlink:to="loc_us-gaap_DerivativeFairValueOfDerivativeLiability_019e41f4-832d-762f-85db-39afe5ed3819" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.firstmerchants.com/role/DERIVATIVEFINANCIALINSTRUMENTSSummaryofEffectofDerivativeFinancialInstrumentsontheIncomeStatementDetails" xlink:type="simple" xlink:href="frme-20260630.xsd#DERIVATIVEFINANCIALINSTRUMENTSSummaryofEffectofDerivativeFinancialInstrumentsontheIncomeStatementDetails"/>
  <link:definitionLink xlink:role="http://www.firstmerchants.com/role/DERIVATIVEFINANCIALINSTRUMENTSSummaryofEffectofDerivativeFinancialInstrumentsontheIncomeStatementDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeLineItems_019e41f4-832d-7641-9928-3b3b2fde83ba" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeTable_019e41f4-832d-797b-a943-a358cbdb5b2d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DerivativeLineItems_019e41f4-832d-7641-9928-3b3b2fde83ba" xlink:to="loc_us-gaap_DerivativeTable_019e41f4-832d-797b-a943-a358cbdb5b2d" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationAxis_019e41f4-832d-79bb-a0ae-1dc33937ea9b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_HedgingDesignationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_019e41f4-832d-797b-a943-a358cbdb5b2d" xlink:to="loc_us-gaap_HedgingDesignationAxis_019e41f4-832d-79bb-a0ae-1dc33937ea9b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationDomain_019e41f4-832d-79bb-a0ae-1dc33937ea9b_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_HedgingDesignationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_HedgingDesignationAxis_019e41f4-832d-79bb-a0ae-1dc33937ea9b" xlink:to="loc_us-gaap_HedgingDesignationDomain_019e41f4-832d-79bb-a0ae-1dc33937ea9b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationDomain_019e41f4-832d-7fbb-a1dc-3a12d3ebea4f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_HedgingDesignationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_HedgingDesignationAxis_019e41f4-832d-79bb-a0ae-1dc33937ea9b" xlink:to="loc_us-gaap_HedgingDesignationDomain_019e41f4-832d-7fbb-a1dc-3a12d3ebea4f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NondesignatedMember_019e41f4-832d-79df-a19d-b41de4f0190d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NondesignatedMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HedgingDesignationDomain_019e41f4-832d-7fbb-a1dc-3a12d3ebea4f" xlink:to="loc_us-gaap_NondesignatedMember_019e41f4-832d-79df-a19d-b41de4f0190d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementOfIncomeLocationBalanceAxis_019e41f4-832d-75dd-838b-b7af349625cd" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementOfIncomeLocationBalanceAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_019e41f4-832d-797b-a943-a358cbdb5b2d" xlink:to="loc_us-gaap_StatementOfIncomeLocationBalanceAxis_019e41f4-832d-75dd-838b-b7af349625cd" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_019e41f4-832d-7282-afc0-33ba5449af59" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeInstrumentRiskAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_019e41f4-832d-797b-a943-a358cbdb5b2d" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_019e41f4-832d-7282-afc0-33ba5449af59" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_019e41f4-832d-7282-afc0-33ba5449af59_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_019e41f4-832d-7282-afc0-33ba5449af59" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_019e41f4-832d-7282-afc0-33ba5449af59_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_019e41f4-832d-7311-8b83-ef866a1a69fb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_019e41f4-832d-7282-afc0-33ba5449af59" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_019e41f4-832d-7311-8b83-ef866a1a69fb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ForwardContractsMember_019e41f4-832d-7c10-9ae2-d0c7c3321e87" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ForwardContractsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_019e41f4-832d-7311-8b83-ef866a1a69fb" xlink:to="loc_us-gaap_ForwardContractsMember_019e41f4-832d-7c10-9ae2-d0c7c3321e87" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestRateLockCommitmentsMember_019e41f4-832d-733d-8c15-ce4c4c91492f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestRateLockCommitmentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_019e41f4-832d-7311-8b83-ef866a1a69fb" xlink:to="loc_us-gaap_InterestRateLockCommitmentsMember_019e41f4-832d-733d-8c15-ce4c4c91492f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentsNotDesignatedAsHedgingInstrumentsGainLossNet_019e41f4-832d-75b0-a21c-c162e2037fc9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeInstrumentsNotDesignatedAsHedgingInstrumentsGainLossNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_019e41f4-832d-7641-9928-3b3b2fde83ba" xlink:to="loc_us-gaap_DerivativeInstrumentsNotDesignatedAsHedgingInstrumentsGainLossNet_019e41f4-832d-75b0-a21c-c162e2037fc9" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.firstmerchants.com/role/DERIVATIVEFINANCIALINSTRUMENTSSummaryofEffectofDerivativeFinancialInstrumentsontheIncomeStatementDetails_1" xlink:type="simple" xlink:href="frme-20260630.xsd#DERIVATIVEFINANCIALINSTRUMENTSSummaryofEffectofDerivativeFinancialInstrumentsontheIncomeStatementDetails_1"/>
  <link:definitionLink xlink:role="http://www.firstmerchants.com/role/DERIVATIVEFINANCIALINSTRUMENTSSummaryofEffectofDerivativeFinancialInstrumentsontheIncomeStatementDetails_1" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeLineItems_019e41f4-832d-7641-9928-3b3b2fde83ba" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeTable_019e41f4-832d-797b-a943-a358cbdb5b2d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DerivativeLineItems_019e41f4-832d-7641-9928-3b3b2fde83ba" xlink:to="loc_us-gaap_DerivativeTable_019e41f4-832d-797b-a943-a358cbdb5b2d" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationAxis_019e41f4-832d-79bb-a0ae-1dc33937ea9b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_HedgingDesignationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_019e41f4-832d-797b-a943-a358cbdb5b2d" xlink:to="loc_us-gaap_HedgingDesignationAxis_019e41f4-832d-79bb-a0ae-1dc33937ea9b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationDomain_019e41f4-832d-79bb-a0ae-1dc33937ea9b_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_HedgingDesignationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_HedgingDesignationAxis_019e41f4-832d-79bb-a0ae-1dc33937ea9b" xlink:to="loc_us-gaap_HedgingDesignationDomain_019e41f4-832d-79bb-a0ae-1dc33937ea9b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationDomain_019e41f4-832d-7fbb-a1dc-3a12d3ebea4f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_HedgingDesignationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_HedgingDesignationAxis_019e41f4-832d-79bb-a0ae-1dc33937ea9b" xlink:to="loc_us-gaap_HedgingDesignationDomain_019e41f4-832d-7fbb-a1dc-3a12d3ebea4f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NondesignatedMember_019e41f4-832d-79df-a19d-b41de4f0190d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NondesignatedMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HedgingDesignationDomain_019e41f4-832d-7fbb-a1dc-3a12d3ebea4f" xlink:to="loc_us-gaap_NondesignatedMember_019e41f4-832d-79df-a19d-b41de4f0190d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_019e41f4-832d-7282-afc0-33ba5449af59" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeInstrumentRiskAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_019e41f4-832d-797b-a943-a358cbdb5b2d" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_019e41f4-832d-7282-afc0-33ba5449af59" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_019e41f4-832d-7282-afc0-33ba5449af59_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_019e41f4-832d-7282-afc0-33ba5449af59" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_019e41f4-832d-7282-afc0-33ba5449af59_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_019e41f4-832d-7311-8b83-ef866a1a69fb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_019e41f4-832d-7282-afc0-33ba5449af59" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_019e41f4-832d-7311-8b83-ef866a1a69fb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ForwardContractsMember_019e41f4-832d-7c10-9ae2-d0c7c3321e87" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ForwardContractsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_019e41f4-832d-7311-8b83-ef866a1a69fb" xlink:to="loc_us-gaap_ForwardContractsMember_019e41f4-832d-7c10-9ae2-d0c7c3321e87" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestRateLockCommitmentsMember_019e41f4-832d-733d-8c15-ce4c4c91492f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestRateLockCommitmentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_019e41f4-832d-7311-8b83-ef866a1a69fb" xlink:to="loc_us-gaap_InterestRateLockCommitmentsMember_019e41f4-832d-733d-8c15-ce4c4c91492f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentsNotDesignatedAsHedgingInstrumentsGainLossNet_019e41f4-832d-75b0-a21c-c162e2037fc9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeInstrumentsNotDesignatedAsHedgingInstrumentsGainLossNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_019e41f4-832d-7641-9928-3b3b2fde83ba" xlink:to="loc_us-gaap_DerivativeInstrumentsNotDesignatedAsHedgingInstrumentsGainLossNet_019e41f4-832d-75b0-a21c-c162e2037fc9" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.firstmerchants.com/role/FAIRVALUESOFFINANCIALINSTRUMENTSSummaryofFairValueMeasurementsofAssetsandLiabilitiesRecognizedintheBalanceSheetsMeasuredatFairValueonRecurringBasisDetails" xlink:type="simple" xlink:href="frme-20260630.xsd#FAIRVALUESOFFINANCIALINSTRUMENTSSummaryofFairValueMeasurementsofAssetsandLiabilitiesRecognizedintheBalanceSheetsMeasuredatFairValueonRecurringBasisDetails"/>
  <link:definitionLink xlink:role="http://www.firstmerchants.com/role/FAIRVALUESOFFINANCIALINSTRUMENTSSummaryofFairValueMeasurementsofAssetsandLiabilitiesRecognizedintheBalanceSheetsMeasuredatFairValueonRecurringBasisDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_019e41f4-832d-7b69-a185-f221dd941252" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByBalanceSheetGroupingTable_019e41f4-832d-702a-943f-89dc4c514ec4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueByBalanceSheetGroupingTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_019e41f4-832d-7b69-a185-f221dd941252" xlink:to="loc_us-gaap_FairValueByBalanceSheetGroupingTable_019e41f4-832d-702a-943f-89dc4c514ec4" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByMeasurementFrequencyAxis_019e41f4-832d-74ef-8bb6-e411696fa91b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueByMeasurementFrequencyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueByBalanceSheetGroupingTable_019e41f4-832d-702a-943f-89dc4c514ec4" xlink:to="loc_us-gaap_FairValueByMeasurementFrequencyAxis_019e41f4-832d-74ef-8bb6-e411696fa91b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_019e41f4-832d-74ef-8bb6-e411696fa91b_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueMeasurementFrequencyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_019e41f4-832d-74ef-8bb6-e411696fa91b" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_019e41f4-832d-74ef-8bb6-e411696fa91b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_019e41f4-832d-7cb0-a7e3-e23a43c61f29" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueMeasurementFrequencyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_019e41f4-832d-74ef-8bb6-e411696fa91b" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_019e41f4-832d-7cb0-a7e3-e23a43c61f29" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsRecurringMember_019e41f4-832d-7da5-87a9-0171421ea423" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueMeasurementsRecurringMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementFrequencyDomain_019e41f4-832d-7cb0-a7e3-e23a43c61f29" xlink:to="loc_us-gaap_FairValueMeasurementsRecurringMember_019e41f4-832d-7da5-87a9-0171421ea423" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_019e41f4-832d-7470-891e-d4ce629542a0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueByBalanceSheetGroupingTable_019e41f4-832d-702a-943f-89dc4c514ec4" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_019e41f4-832d-7470-891e-d4ce629542a0" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019e41f4-832d-7470-891e-d4ce629542a0_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_019e41f4-832d-7470-891e-d4ce629542a0" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019e41f4-832d-7470-891e-d4ce629542a0_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019e41f4-832d-78a4-af53-fb6ababf7d09" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_019e41f4-832d-7470-891e-d4ce629542a0" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019e41f4-832d-78a4-af53-fb6ababf7d09" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel1Member_019e41f4-832d-7ba1-ac5f-d75f866e21ca" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueInputsLevel1Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019e41f4-832d-78a4-af53-fb6ababf7d09" xlink:to="loc_us-gaap_FairValueInputsLevel1Member_019e41f4-832d-7ba1-ac5f-d75f866e21ca" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel2Member_019e41f4-832d-70df-90a2-dd33897af7fa" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueInputsLevel2Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019e41f4-832d-78a4-af53-fb6ababf7d09" xlink:to="loc_us-gaap_FairValueInputsLevel2Member_019e41f4-832d-70df-90a2-dd33897af7fa" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel3Member_019e41f4-832d-769c-94aa-92286d38ca93" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueInputsLevel3Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019e41f4-832d-78a4-af53-fb6ababf7d09" xlink:to="loc_us-gaap_FairValueInputsLevel3Member_019e41f4-832d-769c-94aa-92286d38ca93" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentAxis_019e41f4-832d-7db9-8ebc-b89713031167" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancialInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueByBalanceSheetGroupingTable_019e41f4-832d-702a-943f-89dc4c514ec4" xlink:to="loc_us-gaap_FinancialInstrumentAxis_019e41f4-832d-7db9-8ebc-b89713031167" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e41f4-832d-7db9-8ebc-b89713031167_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentAxis_019e41f4-832d-7db9-8ebc-b89713031167" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e41f4-832d-7db9-8ebc-b89713031167_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e41f4-832d-70a8-9303-31cb4b7d5e61" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentAxis_019e41f4-832d-7db9-8ebc-b89713031167" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e41f4-832d-70a8-9303-31cb4b7d5e61" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_USGovernmentAgenciesDebtSecuritiesMember_019e41f4-832d-75a6-994f-f379b6a9383a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_USGovernmentAgenciesDebtSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e41f4-832d-70a8-9303-31cb4b7d5e61" xlink:to="loc_us-gaap_USGovernmentAgenciesDebtSecuritiesMember_019e41f4-832d-75a6-994f-f379b6a9383a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_USStatesAndPoliticalSubdivisionsMember_019e41f4-832d-78d2-a08d-e9b72e087982" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_USStatesAndPoliticalSubdivisionsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e41f4-832d-70a8-9303-31cb4b7d5e61" xlink:to="loc_us-gaap_USStatesAndPoliticalSubdivisionsMember_019e41f4-832d-78d2-a08d-e9b72e087982" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember_019e41f4-832d-7422-b592-9b318473561c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e41f4-832d-70a8-9303-31cb4b7d5e61" xlink:to="loc_us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember_019e41f4-832d-7422-b592-9b318473561c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ForeignGovernmentDebtSecuritiesMember_019e41f4-832d-7d5d-95a3-71c8d098a1d7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ForeignGovernmentDebtSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e41f4-832d-70a8-9303-31cb4b7d5e61" xlink:to="loc_us-gaap_ForeignGovernmentDebtSecuritiesMember_019e41f4-832d-7d5d-95a3-71c8d098a1d7" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CorporateDebtSecuritiesMember_019e41f4-832d-77eb-b3b4-7d4add066572" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CorporateDebtSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e41f4-832d-70a8-9303-31cb4b7d5e61" xlink:to="loc_us-gaap_CorporateDebtSecuritiesMember_019e41f4-832d-77eb-b3b4-7d4add066572" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtSecurities_019e41f4-832d-7699-8de5-65ed3fbae569" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AvailableForSaleSecuritiesDebtSecurities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_019e41f4-832d-7b69-a185-f221dd941252" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtSecurities_019e41f4-832d-7699-8de5-65ed3fbae569" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeFairValueOfDerivativeAsset_019e41f4-832d-7785-8854-bc5513c45d11" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeFairValueOfDerivativeAsset"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_019e41f4-832d-7b69-a185-f221dd941252" xlink:to="loc_us-gaap_DerivativeFairValueOfDerivativeAsset_019e41f4-832d-7785-8854-bc5513c45d11" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeFairValueOfDerivativeLiability_019e41f4-832d-7cea-9ab0-6f456c791ceb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeFairValueOfDerivativeLiability"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_019e41f4-832d-7b69-a185-f221dd941252" xlink:to="loc_us-gaap_DerivativeFairValueOfDerivativeLiability_019e41f4-832d-7cea-9ab0-6f456c791ceb" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.firstmerchants.com/role/FAIRVALUESOFFINANCIALINSTRUMENTSSummaryofReconciliationofBeginningandEndingBalancesofRecurringFairValueMeasurementsRecognizedintheBalanceSheetsusingSignificantUnobservableLevel3InputsDetails" xlink:type="simple" xlink:href="frme-20260630.xsd#FAIRVALUESOFFINANCIALINSTRUMENTSSummaryofReconciliationofBeginningandEndingBalancesofRecurringFairValueMeasurementsRecognizedintheBalanceSheetsusingSignificantUnobservableLevel3InputsDetails"/>
  <link:definitionLink xlink:role="http://www.firstmerchants.com/role/FAIRVALUESOFFINANCIALINSTRUMENTSSummaryofReconciliationofBeginningandEndingBalancesofRecurringFairValueMeasurementsRecognizedintheBalanceSheetsusingSignificantUnobservableLevel3InputsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_019e41f4-832d-7c92-8334-40006a1e1ee9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByBalanceSheetGroupingTable_019e41f4-832d-757f-ae03-216a638da2bc" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueByBalanceSheetGroupingTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_019e41f4-832d-7c92-8334-40006a1e1ee9" xlink:to="loc_us-gaap_FairValueByBalanceSheetGroupingTable_019e41f4-832d-757f-ae03-216a638da2bc" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByMeasurementFrequencyAxis_019e41f4-832d-7922-b59b-0fba822b27eb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueByMeasurementFrequencyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueByBalanceSheetGroupingTable_019e41f4-832d-757f-ae03-216a638da2bc" xlink:to="loc_us-gaap_FairValueByMeasurementFrequencyAxis_019e41f4-832d-7922-b59b-0fba822b27eb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_019e41f4-832d-7922-b59b-0fba822b27eb_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueMeasurementFrequencyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_019e41f4-832d-7922-b59b-0fba822b27eb" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_019e41f4-832d-7922-b59b-0fba822b27eb_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_019e41f4-832d-7bc2-af3a-a2bc26b4795a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueMeasurementFrequencyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_019e41f4-832d-7922-b59b-0fba822b27eb" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_019e41f4-832d-7bc2-af3a-a2bc26b4795a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsRecurringMember_019e41f4-832d-7892-b44b-67468ed79b37" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueMeasurementsRecurringMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementFrequencyDomain_019e41f4-832d-7bc2-af3a-a2bc26b4795a" xlink:to="loc_us-gaap_FairValueMeasurementsRecurringMember_019e41f4-832d-7892-b44b-67468ed79b37" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_019e41f4-832d-797a-862f-85349476ef5a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_019e41f4-832d-7c92-8334-40006a1e1ee9" xlink:to="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_019e41f4-832d-797a-862f-85349476ef5a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue_019e41f4-832d-7155-ad06-a703a0dbb387" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_019e41f4-832d-797a-862f-85349476ef5a" xlink:to="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue_019e41f4-832d-7155-ad06-a703a0dbb387" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPurchases_019e41f4-832d-7644-85b5-48d8aff41877" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPurchases"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_019e41f4-832d-797a-862f-85349476ef5a" xlink:to="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPurchases_019e41f4-832d-7644-85b5-48d8aff41877" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInOtherComprehensiveIncomeLoss_019e41f4-832d-77ab-b3b4-de72c5671ad1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInOtherComprehensiveIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_019e41f4-832d-797a-862f-85349476ef5a" xlink:to="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInOtherComprehensiveIncomeLoss_019e41f4-832d-77ab-b3b4-de72c5671ad1" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPrincipalPayments_019e41f4-832d-7b4f-ad4d-6c2cb8730092" xlink:href="frme-20260630.xsd#frme_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPrincipalPayments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_019e41f4-832d-797a-862f-85349476ef5a" xlink:to="loc_frme_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPrincipalPayments_019e41f4-832d-7b4f-ad4d-6c2cb8730092" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue_019e41f4-832d-7e89-9933-8b006c81c754" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.firstmerchants.com/role/FAIRVALUESOFFINANCIALINSTRUMENTSSummaryofDescriptionofValuationMethodologiesUsedforInstrumentsMeasuredatFairValueonaNonRecurringBasisandRecognizedintheBalanceSheetsDetails" xlink:type="simple" xlink:href="frme-20260630.xsd#FAIRVALUESOFFINANCIALINSTRUMENTSSummaryofDescriptionofValuationMethodologiesUsedforInstrumentsMeasuredatFairValueonaNonRecurringBasisandRecognizedintheBalanceSheetsDetails"/>
  <link:definitionLink xlink:role="http://www.firstmerchants.com/role/FAIRVALUESOFFINANCIALINSTRUMENTSSummaryofDescriptionofValuationMethodologiesUsedforInstrumentsMeasuredatFairValueonaNonRecurringBasisandRecognizedintheBalanceSheetsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_019e41f4-832d-72ed-92b3-aa188eb67af9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_019e41f4-832d-7844-8aee-e39747205688" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_019e41f4-832d-72ed-92b3-aa188eb67af9" xlink:to="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_019e41f4-832d-7844-8aee-e39747205688" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByMeasurementFrequencyAxis_019e41f4-832d-7fb1-b06e-d0d26006a669" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueByMeasurementFrequencyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_019e41f4-832d-7844-8aee-e39747205688" xlink:to="loc_us-gaap_FairValueByMeasurementFrequencyAxis_019e41f4-832d-7fb1-b06e-d0d26006a669" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_019e41f4-832d-7fb1-b06e-d0d26006a669_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueMeasurementFrequencyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_019e41f4-832d-7fb1-b06e-d0d26006a669" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_019e41f4-832d-7fb1-b06e-d0d26006a669_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_019e41f4-832d-7324-9c99-7c265764569e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueMeasurementFrequencyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_019e41f4-832d-7fb1-b06e-d0d26006a669" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_019e41f4-832d-7324-9c99-7c265764569e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsNonrecurringMember_019e41f4-832d-7b92-b62d-0b7c2daee0e4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueMeasurementsNonrecurringMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementFrequencyDomain_019e41f4-832d-7324-9c99-7c265764569e" xlink:to="loc_us-gaap_FairValueMeasurementsNonrecurringMember_019e41f4-832d-7b92-b62d-0b7c2daee0e4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentAxis_019e41f4-832d-7dfb-bbb7-9387c855c718" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancialInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_019e41f4-832d-7844-8aee-e39747205688" xlink:to="loc_us-gaap_FinancialInstrumentAxis_019e41f4-832d-7dfb-bbb7-9387c855c718" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e41f4-832d-7dfb-bbb7-9387c855c718_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentAxis_019e41f4-832d-7dfb-bbb7-9387c855c718" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e41f4-832d-7dfb-bbb7-9387c855c718_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e41f4-832d-7efa-8678-4e26f3e5fde2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentAxis_019e41f4-832d-7dfb-bbb7-9387c855c718" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e41f4-832d-7efa-8678-4e26f3e5fde2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_CollateralDependentLoansMember_019e41f4-832d-7f30-8927-4424a19008eb" xlink:href="frme-20260630.xsd#frme_CollateralDependentLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e41f4-832d-7efa-8678-4e26f3e5fde2" xlink:to="loc_frme_CollateralDependentLoansMember_019e41f4-832d-7f30-8927-4424a19008eb" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_019e41f4-832d-733a-81cc-12fca2117a1a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_019e41f4-832d-7844-8aee-e39747205688" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_019e41f4-832d-733a-81cc-12fca2117a1a" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019e41f4-832d-733a-81cc-12fca2117a1a_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_019e41f4-832d-733a-81cc-12fca2117a1a" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019e41f4-832d-733a-81cc-12fca2117a1a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019e41f4-832d-7892-a2b9-efdf9ef97e1d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_019e41f4-832d-733a-81cc-12fca2117a1a" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019e41f4-832d-7892-a2b9-efdf9ef97e1d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel1Member_019e41f4-832d-7ac5-847b-5bbaca9da125" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueInputsLevel1Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019e41f4-832d-7892-a2b9-efdf9ef97e1d" xlink:to="loc_us-gaap_FairValueInputsLevel1Member_019e41f4-832d-7ac5-847b-5bbaca9da125" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel2Member_019e41f4-832d-7849-8492-293b5e48f558" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueInputsLevel2Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019e41f4-832d-7892-a2b9-efdf9ef97e1d" xlink:to="loc_us-gaap_FairValueInputsLevel2Member_019e41f4-832d-7849-8492-293b5e48f558" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel3Member_019e41f4-832d-7991-96d8-457d98c756de" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueInputsLevel3Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019e41f4-832d-7892-a2b9-efdf9ef97e1d" xlink:to="loc_us-gaap_FairValueInputsLevel3Member_019e41f4-832d-7991-96d8-457d98c756de" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsFairValueDisclosure_019e41f4-832d-7948-9b0a-a6a7ccd9d99f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetsFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_019e41f4-832d-72ed-92b3-aa188eb67af9" xlink:to="loc_us-gaap_AssetsFairValueDisclosure_019e41f4-832d-7948-9b0a-a6a7ccd9d99f" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.firstmerchants.com/role/FAIRVALUESOFFINANCIALINSTRUMENTSSummaryofUnobservableInputsUsedinRecurringandNonrecurringLevel3FairValueMeasurementsOtherthanGoodwillDetails" xlink:type="simple" xlink:href="frme-20260630.xsd#FAIRVALUESOFFINANCIALINSTRUMENTSSummaryofUnobservableInputsUsedinRecurringandNonrecurringLevel3FairValueMeasurementsOtherthanGoodwillDetails"/>
  <link:definitionLink xlink:role="http://www.firstmerchants.com/role/FAIRVALUESOFFINANCIALINSTRUMENTSSummaryofUnobservableInputsUsedinRecurringandNonrecurringLevel3FairValueMeasurementsOtherthanGoodwillDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems_019e41f4-832d-781b-b262-03621974836f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTable_019e41f4-832d-7128-aaa5-f438a9a7b777" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems_019e41f4-832d-781b-b262-03621974836f" xlink:to="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTable_019e41f4-832d-7128-aaa5-f438a9a7b777" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_019e41f4-832d-73a5-ae08-099210a9d2ee" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTable_019e41f4-832d-7128-aaa5-f438a9a7b777" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_019e41f4-832d-73a5-ae08-099210a9d2ee" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019e41f4-832d-73a5-ae08-099210a9d2ee_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_019e41f4-832d-73a5-ae08-099210a9d2ee" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019e41f4-832d-73a5-ae08-099210a9d2ee_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019e41f4-832d-7c62-b3c0-8310fd7a637d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_019e41f4-832d-73a5-ae08-099210a9d2ee" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019e41f4-832d-7c62-b3c0-8310fd7a637d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel3Member_019e41f4-832d-7aad-9d9f-d59b2ebe900a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueInputsLevel3Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019e41f4-832d-7c62-b3c0-8310fd7a637d" xlink:to="loc_us-gaap_FairValueInputsLevel3Member_019e41f4-832d-7aad-9d9f-d59b2ebe900a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentAxis_019e41f4-832d-7ce5-bd84-9c56483c2f3e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancialInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTable_019e41f4-832d-7128-aaa5-f438a9a7b777" xlink:to="loc_us-gaap_FinancialInstrumentAxis_019e41f4-832d-7ce5-bd84-9c56483c2f3e" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e41f4-832d-7ce5-bd84-9c56483c2f3e_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentAxis_019e41f4-832d-7ce5-bd84-9c56483c2f3e" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e41f4-832d-7ce5-bd84-9c56483c2f3e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e41f4-832d-7311-a089-de668261fab1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentAxis_019e41f4-832d-7ce5-bd84-9c56483c2f3e" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e41f4-832d-7311-a089-de668261fab1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_USStatesAndPoliticalSubdivisionsMember_019e41f4-832d-7675-bd3c-521e9dcdfe93" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_USStatesAndPoliticalSubdivisionsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e41f4-832d-7311-a089-de668261fab1" xlink:to="loc_us-gaap_USStatesAndPoliticalSubdivisionsMember_019e41f4-832d-7675-bd3c-521e9dcdfe93" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CorporateDebtSecuritiesMember_019e41f4-832d-79ba-9528-a285b3d7c681" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CorporateDebtSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e41f4-832d-7311-a089-de668261fab1" xlink:to="loc_us-gaap_CorporateDebtSecuritiesMember_019e41f4-832d-79ba-9528-a285b3d7c681" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_CorporateObligationsandU.S.GovernmentSponsoredMortgageBackedSecuritiesMember_019e41f4-832d-71e5-9d81-8d839a9826d9" xlink:href="frme-20260630.xsd#frme_CorporateObligationsandU.S.GovernmentSponsoredMortgageBackedSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e41f4-832d-7311-a089-de668261fab1" xlink:to="loc_frme_CorporateObligationsandU.S.GovernmentSponsoredMortgageBackedSecuritiesMember_019e41f4-832d-71e5-9d81-8d839a9826d9" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_CollateralDependentLoansMember_019e41f4-832d-7d17-b87e-1d8c84a2adb9" xlink:href="frme-20260630.xsd#frme_CollateralDependentLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019e41f4-832d-7311-a089-de668261fab1" xlink:to="loc_frme_CollateralDependentLoansMember_019e41f4-832d-7d17-b87e-1d8c84a2adb9" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationTechniqueAxis_019e41f4-832d-7cbd-9c22-b285890ad1ce" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ValuationTechniqueAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTable_019e41f4-832d-7128-aaa5-f438a9a7b777" xlink:to="loc_us-gaap_ValuationTechniqueAxis_019e41f4-832d-7cbd-9c22-b285890ad1ce" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationTechniqueDomain_019e41f4-832d-7cbd-9c22-b285890ad1ce_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ValuationTechniqueDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ValuationTechniqueAxis_019e41f4-832d-7cbd-9c22-b285890ad1ce" xlink:to="loc_us-gaap_ValuationTechniqueDomain_019e41f4-832d-7cbd-9c22-b285890ad1ce_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationTechniqueDomain_019e41f4-832d-7ac7-9002-3d4be9366dc8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ValuationTechniqueDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ValuationTechniqueAxis_019e41f4-832d-7cbd-9c22-b285890ad1ce" xlink:to="loc_us-gaap_ValuationTechniqueDomain_019e41f4-832d-7ac7-9002-3d4be9366dc8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationTechniqueDiscountedCashFlowMember_019e41f4-832d-7ef0-a677-2b8451a09b58" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ValuationTechniqueDiscountedCashFlowMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ValuationTechniqueDomain_019e41f4-832d-7ac7-9002-3d4be9366dc8" xlink:to="loc_us-gaap_ValuationTechniqueDiscountedCashFlowMember_019e41f4-832d-7ef0-a677-2b8451a09b58" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_CollateralBasedMeasurementsMember_019e41f4-832d-7a72-aa29-f023e136f1fc" xlink:href="frme-20260630.xsd#frme_CollateralBasedMeasurementsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ValuationTechniqueDomain_019e41f4-832d-7ac7-9002-3d4be9366dc8" xlink:to="loc_frme_CollateralBasedMeasurementsMember_019e41f4-832d-7a72-aa29-f023e136f1fc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputTypeAxis_019e41f4-832d-7b47-8ca8-206b29d9a7dc" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_MeasurementInputTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTable_019e41f4-832d-7128-aaa5-f438a9a7b777" xlink:to="loc_us-gaap_MeasurementInputTypeAxis_019e41f4-832d-7b47-8ca8-206b29d9a7dc" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputTypeDomain_019e41f4-832d-7b47-8ca8-206b29d9a7dc_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_MeasurementInputTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_MeasurementInputTypeAxis_019e41f4-832d-7b47-8ca8-206b29d9a7dc" xlink:to="loc_us-gaap_MeasurementInputTypeDomain_019e41f4-832d-7b47-8ca8-206b29d9a7dc_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputTypeDomain_019e41f4-832d-72d4-9d7f-48d634ce55bf" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_MeasurementInputTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_MeasurementInputTypeAxis_019e41f4-832d-7b47-8ca8-206b29d9a7dc" xlink:to="loc_us-gaap_MeasurementInputTypeDomain_019e41f4-832d-72d4-9d7f-48d634ce55bf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputDiscountRateMember_019e41f4-832d-74a0-b395-fea6215ad496" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_MeasurementInputDiscountRateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MeasurementInputTypeDomain_019e41f4-832d-72d4-9d7f-48d634ce55bf" xlink:to="loc_us-gaap_MeasurementInputDiscountRateMember_019e41f4-832d-74a0-b395-fea6215ad496" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_MeasurementInputCouponRateMember_019e41f4-832d-7407-9f28-d10376d9d608" xlink:href="frme-20260630.xsd#frme_MeasurementInputCouponRateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MeasurementInputTypeDomain_019e41f4-832d-72d4-9d7f-48d634ce55bf" xlink:to="loc_frme_MeasurementInputCouponRateMember_019e41f4-832d-7407-9f28-d10376d9d608" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputRiskFreeInterestRateMember_019e41f4-832d-7ec2-b7b4-77a8d635ff48" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_MeasurementInputRiskFreeInterestRateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MeasurementInputTypeDomain_019e41f4-832d-72d4-9d7f-48d634ce55bf" xlink:to="loc_us-gaap_MeasurementInputRiskFreeInterestRateMember_019e41f4-832d-7ec2-b7b4-77a8d635ff48" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputDiscountForLackOfMarketabilityMember_019e41f4-832d-7acc-8398-5ce1e97bd81a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_MeasurementInputDiscountForLackOfMarketabilityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MeasurementInputTypeDomain_019e41f4-832d-72d4-9d7f-48d634ce55bf" xlink:to="loc_us-gaap_MeasurementInputDiscountForLackOfMarketabilityMember_019e41f4-832d-7acc-8398-5ce1e97bd81a" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputComparabilityAdjustmentMember_019e41f4-832d-7a61-aa09-037c543312fb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_MeasurementInputComparabilityAdjustmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MeasurementInputTypeDomain_019e41f4-832d-72d4-9d7f-48d634ce55bf" xlink:to="loc_us-gaap_MeasurementInputComparabilityAdjustmentMember_019e41f4-832d-7a61-aa09-037c543312fb" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_MeasurementInputDiscountByLoanBalanceMember_019e41f4-832d-7c2b-8446-7ac4e20cc589" xlink:href="frme-20260630.xsd#frme_MeasurementInputDiscountByLoanBalanceMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MeasurementInputTypeDomain_019e41f4-832d-72d4-9d7f-48d634ce55bf" xlink:to="loc_frme_MeasurementInputDiscountByLoanBalanceMember_019e41f4-832d-7c2b-8446-7ac4e20cc589" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_019e41f4-832d-76d1-b3e7-32d2053c8939" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTable_019e41f4-832d-7128-aaa5-f438a9a7b777" xlink:to="loc_srt_RangeAxis_019e41f4-832d-76d1-b3e7-32d2053c8939" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_019e41f4-832d-76d1-b3e7-32d2053c8939_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_019e41f4-832d-76d1-b3e7-32d2053c8939" xlink:to="loc_srt_RangeMember_019e41f4-832d-76d1-b3e7-32d2053c8939_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_019e41f4-832d-7bd8-9c0d-52301ccca039" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_019e41f4-832d-76d1-b3e7-32d2053c8939" xlink:to="loc_srt_RangeMember_019e41f4-832d-7bd8-9c0d-52301ccca039" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_019e41f4-832d-77ca-913b-3236e71148e7" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_019e41f4-832d-7bd8-9c0d-52301ccca039" xlink:to="loc_srt_MinimumMember_019e41f4-832d-77ca-913b-3236e71148e7" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_019e41f4-832d-7bbf-8e98-6f134de874ed" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_019e41f4-832d-7bd8-9c0d-52301ccca039" xlink:to="loc_srt_MaximumMember_019e41f4-832d-7bbf-8e98-6f134de874ed" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_WeightedAverageMember_019e41f4-832d-7bcd-899f-f2a5d38301d9" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_WeightedAverageMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_019e41f4-832d-7bd8-9c0d-52301ccca039" xlink:to="loc_srt_WeightedAverageMember_019e41f4-832d-7bcd-899f-f2a5d38301d9" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsFairValueDisclosure_019e41f4-832d-749b-ae05-ddad509a18e2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetsFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems_019e41f4-832d-781b-b262-03621974836f" xlink:to="loc_us-gaap_AssetsFairValueDisclosure_019e41f4-832d-749b-ae05-ddad509a18e2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleTerm_019e41f4-832d-75aa-bfcf-10b0cbcbcd26" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtSecuritiesAvailableForSaleTerm"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems_019e41f4-832d-781b-b262-03621974836f" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleTerm_019e41f4-832d-75aa-bfcf-10b0cbcbcd26" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentCreditRating_019e41f4-832d-7ae4-b7f6-34754265318c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentCreditRating"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems_019e41f4-832d-781b-b262-03621974836f" xlink:to="loc_us-gaap_DebtInstrumentCreditRating_019e41f4-832d-7ae4-b7f6-34754265318c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleMeasurementInput_019e41f4-832d-72b5-b857-917c7fabae9e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtSecuritiesAvailableForSaleMeasurementInput"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems_019e41f4-832d-781b-b262-03621974836f" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleMeasurementInput_019e41f4-832d-72b5-b857-917c7fabae9e" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_ImpairedLoansMeasurementInput_019e41f4-832d-71f7-aa76-4529a46d7ac5" xlink:href="frme-20260630.xsd#frme_ImpairedLoansMeasurementInput"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems_019e41f4-832d-781b-b262-03621974836f" xlink:to="loc_frme_ImpairedLoansMeasurementInput_019e41f4-832d-71f7-aa76-4529a46d7ac5" xlink:type="arc" order="4"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.firstmerchants.com/role/FAIRVALUESOFFINANCIALINSTRUMENTSSummaryofEstimatedFairValuesofFinancialInstrumentsDetails" xlink:type="simple" xlink:href="frme-20260630.xsd#FAIRVALUESOFFINANCIALINSTRUMENTSSummaryofEstimatedFairValuesofFinancialInstrumentsDetails"/>
  <link:definitionLink xlink:role="http://www.firstmerchants.com/role/FAIRVALUESOFFINANCIALINSTRUMENTSSummaryofEstimatedFairValuesofFinancialInstrumentsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_019e41f4-832d-7104-bcdc-dcd3d36e0eb8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByBalanceSheetGroupingTable_019e41f4-832d-7afb-b4f1-359d065e6020" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueByBalanceSheetGroupingTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_019e41f4-832d-7104-bcdc-dcd3d36e0eb8" xlink:to="loc_us-gaap_FairValueByBalanceSheetGroupingTable_019e41f4-832d-7afb-b4f1-359d065e6020" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByMeasurementBasisAxis_019e41f4-832d-78db-a4b3-546434e81f1e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueByMeasurementBasisAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueByBalanceSheetGroupingTable_019e41f4-832d-7afb-b4f1-359d065e6020" xlink:to="loc_us-gaap_FairValueByMeasurementBasisAxis_019e41f4-832d-78db-a4b3-546434e81f1e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_019e41f4-832d-78db-a4b3-546434e81f1e_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PortionAtFairValueFairValueDisclosureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByMeasurementBasisAxis_019e41f4-832d-78db-a4b3-546434e81f1e" xlink:to="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_019e41f4-832d-78db-a4b3-546434e81f1e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueDisclosureItemAmountsDomain_019e41f4-832d-77d1-9d2b-724e233f1ab3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueDisclosureItemAmountsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByMeasurementBasisAxis_019e41f4-832d-78db-a4b3-546434e81f1e" xlink:to="loc_us-gaap_FairValueDisclosureItemAmountsDomain_019e41f4-832d-77d1-9d2b-724e233f1ab3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_019e41f4-832d-7fb9-b98b-1c61f17570ca" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PortionAtFairValueFairValueDisclosureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueDisclosureItemAmountsDomain_019e41f4-832d-77d1-9d2b-724e233f1ab3" xlink:to="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_019e41f4-832d-7fb9-b98b-1c61f17570ca" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CarryingReportedAmountFairValueDisclosureMember_019e41f4-832d-716a-a9ad-3451768bf37d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CarryingReportedAmountFairValueDisclosureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_019e41f4-832d-7fb9-b98b-1c61f17570ca" xlink:to="loc_us-gaap_CarryingReportedAmountFairValueDisclosureMember_019e41f4-832d-716a-a9ad-3451768bf37d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_019e41f4-832d-7fc5-805d-3a38cd994642" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueByBalanceSheetGroupingTable_019e41f4-832d-7afb-b4f1-359d065e6020" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_019e41f4-832d-7fc5-805d-3a38cd994642" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019e41f4-832d-7fc5-805d-3a38cd994642_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_019e41f4-832d-7fc5-805d-3a38cd994642" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019e41f4-832d-7fc5-805d-3a38cd994642_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019e41f4-832d-777f-8dd1-3c21cdfc7e0e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_019e41f4-832d-7fc5-805d-3a38cd994642" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019e41f4-832d-777f-8dd1-3c21cdfc7e0e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel1Member_019e41f4-832d-7aa0-8753-6810eaadfaed" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueInputsLevel1Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019e41f4-832d-777f-8dd1-3c21cdfc7e0e" xlink:to="loc_us-gaap_FairValueInputsLevel1Member_019e41f4-832d-7aa0-8753-6810eaadfaed" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel2Member_019e41f4-832d-7371-94ec-b4a9ec999303" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueInputsLevel2Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019e41f4-832d-777f-8dd1-3c21cdfc7e0e" xlink:to="loc_us-gaap_FairValueInputsLevel2Member_019e41f4-832d-7371-94ec-b4a9ec999303" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel3Member_019e41f4-832d-7720-ae67-d3a47c4bcb19" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueInputsLevel3Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019e41f4-832d-777f-8dd1-3c21cdfc7e0e" xlink:to="loc_us-gaap_FairValueInputsLevel3Member_019e41f4-832d-7720-ae67-d3a47c4bcb19" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentsFinancialAssetsBalanceSheetGroupingsAbstract_019e41f4-832d-733e-ac51-c97a0175e33d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancialInstrumentsFinancialAssetsBalanceSheetGroupingsAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_019e41f4-832d-7104-bcdc-dcd3d36e0eb8" xlink:to="loc_us-gaap_FinancialInstrumentsFinancialAssetsBalanceSheetGroupingsAbstract_019e41f4-832d-733e-ac51-c97a0175e33d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndCashEquivalentsFairValueDisclosure_019e41f4-832d-7417-b6a2-1ce5da1d841a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CashAndCashEquivalentsFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancialInstrumentsFinancialAssetsBalanceSheetGroupingsAbstract_019e41f4-832d-733e-ac51-c97a0175e33d" xlink:to="loc_us-gaap_CashAndCashEquivalentsFairValueDisclosure_019e41f4-832d-7417-b6a2-1ce5da1d841a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_InterestBearingDepositsWithBanksFairValueDisclosure_019e41f4-832d-7caa-b762-7e08a2e4fdaa" xlink:href="frme-20260630.xsd#frme_InterestBearingDepositsWithBanksFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancialInstrumentsFinancialAssetsBalanceSheetGroupingsAbstract_019e41f4-832d-733e-ac51-c97a0175e33d" xlink:to="loc_frme_InterestBearingDepositsWithBanksFairValueDisclosure_019e41f4-832d-7caa-b762-7e08a2e4fdaa" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HeldToMaturitySecuritiesFairValue_019e41f4-832d-7a9a-a487-4de05543042d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_HeldToMaturitySecuritiesFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancialInstrumentsFinancialAssetsBalanceSheetGroupingsAbstract_019e41f4-832d-733e-ac51-c97a0175e33d" xlink:to="loc_us-gaap_HeldToMaturitySecuritiesFairValue_019e41f4-832d-7a9a-a487-4de05543042d" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LoansHeldForSaleFairValueDisclosure_019e41f4-832d-7206-84bc-d8950748d887" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LoansHeldForSaleFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancialInstrumentsFinancialAssetsBalanceSheetGroupingsAbstract_019e41f4-832d-733e-ac51-c97a0175e33d" xlink:to="loc_us-gaap_LoansHeldForSaleFairValueDisclosure_019e41f4-832d-7206-84bc-d8950748d887" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LoansReceivableFairValueDisclosure_019e41f4-832d-7c0e-88c4-cfde9094997f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LoansReceivableFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancialInstrumentsFinancialAssetsBalanceSheetGroupingsAbstract_019e41f4-832d-733e-ac51-c97a0175e33d" xlink:to="loc_us-gaap_LoansReceivableFairValueDisclosure_019e41f4-832d-7c0e-88c4-cfde9094997f" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentInFederalHomeLoanBankStockFairValueDisclosure_019e41f4-832d-7509-9b59-eae59030109d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InvestmentInFederalHomeLoanBankStockFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancialInstrumentsFinancialAssetsBalanceSheetGroupingsAbstract_019e41f4-832d-733e-ac51-c97a0175e33d" xlink:to="loc_us-gaap_InvestmentInFederalHomeLoanBankStockFairValueDisclosure_019e41f4-832d-7509-9b59-eae59030109d" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_InterestReceivableFairValueDisclosure_019e41f4-832d-7827-a39c-eba368d463f9" xlink:href="frme-20260630.xsd#frme_InterestReceivableFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancialInstrumentsFinancialAssetsBalanceSheetGroupingsAbstract_019e41f4-832d-733e-ac51-c97a0175e33d" xlink:to="loc_frme_InterestReceivableFairValueDisclosure_019e41f4-832d-7827-a39c-eba368d463f9" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentsFinancialLiabilitiesBalanceSheetGroupingsAbstract_019e41f4-832d-7997-822d-7a4e34b126cf" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancialInstrumentsFinancialLiabilitiesBalanceSheetGroupingsAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_019e41f4-832d-7104-bcdc-dcd3d36e0eb8" xlink:to="loc_us-gaap_FinancialInstrumentsFinancialLiabilitiesBalanceSheetGroupingsAbstract_019e41f4-832d-7997-822d-7a4e34b126cf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DepositsFairValueDisclosure_019e41f4-832d-731b-9245-eb981fe4e54a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DepositsFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancialInstrumentsFinancialLiabilitiesBalanceSheetGroupingsAbstract_019e41f4-832d-7997-822d-7a4e34b126cf" xlink:to="loc_us-gaap_DepositsFairValueDisclosure_019e41f4-832d-731b-9245-eb981fe4e54a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_BorrowedFundsAbstract_019e41f4-832d-73c4-b966-bfee795e47af" xlink:href="frme-20260630.xsd#frme_BorrowedFundsAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancialInstrumentsFinancialLiabilitiesBalanceSheetGroupingsAbstract_019e41f4-832d-7997-822d-7a4e34b126cf" xlink:to="loc_frme_BorrowedFundsAbstract_019e41f4-832d-73c4-b966-bfee795e47af" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FederalFundsPurchasedFairValueDisclosure_019e41f4-832d-7dfc-9de3-63f8fcf1afd2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FederalFundsPurchasedFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_frme_BorrowedFundsAbstract_019e41f4-832d-73c4-b966-bfee795e47af" xlink:to="loc_us-gaap_FederalFundsPurchasedFairValueDisclosure_019e41f4-832d-7dfc-9de3-63f8fcf1afd2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SecuritiesLoanedOrSoldUnderAgreementsToRepurchaseFairValueDisclosure_019e41f4-832d-747a-a68b-fef1b47bba98" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SecuritiesLoanedOrSoldUnderAgreementsToRepurchaseFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_frme_BorrowedFundsAbstract_019e41f4-832d-73c4-b966-bfee795e47af" xlink:to="loc_us-gaap_SecuritiesLoanedOrSoldUnderAgreementsToRepurchaseFairValueDisclosure_019e41f4-832d-747a-a68b-fef1b47bba98" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FederalHomeLoanBankBorrowingsFairValueDisclosure_019e41f4-832d-7a8f-ac5a-e0341bf0157d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FederalHomeLoanBankBorrowingsFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_frme_BorrowedFundsAbstract_019e41f4-832d-73c4-b966-bfee795e47af" xlink:to="loc_us-gaap_FederalHomeLoanBankBorrowingsFairValueDisclosure_019e41f4-832d-7a8f-ac5a-e0341bf0157d" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherLiabilitiesFairValueDisclosure_019e41f4-832d-7ec2-b65d-4bd9ca617f19" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherLiabilitiesFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_frme_BorrowedFundsAbstract_019e41f4-832d-73c4-b966-bfee795e47af" xlink:to="loc_us-gaap_OtherLiabilitiesFairValueDisclosure_019e41f4-832d-7ec2-b65d-4bd9ca617f19" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_InterestPayableFairValueDisclosure_019e41f4-832d-726f-bafb-55d14f9b5d15" xlink:href="frme-20260630.xsd#frme_InterestPayableFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancialInstrumentsFinancialLiabilitiesBalanceSheetGroupingsAbstract_019e41f4-832d-7997-822d-7a4e34b126cf" xlink:to="loc_frme_InterestPayableFairValueDisclosure_019e41f4-832d-726f-bafb-55d14f9b5d15" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.firstmerchants.com/role/BORROWINGSNarrativeDetails" xlink:type="simple" xlink:href="frme-20260630.xsd#BORROWINGSNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.firstmerchants.com/role/BORROWINGSNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentLineItems_019e41f4-832d-7476-9b32-520717e4379d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTable_019e41f4-832d-7d38-bc97-0cae7fc3b0c4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019e41f4-832d-7476-9b32-520717e4379d" xlink:to="loc_us-gaap_DebtInstrumentTable_019e41f4-832d-7d38-bc97-0cae7fc3b0c4" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_019e41f4-832d-7592-b1c7-fc64d4a2b8fe" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_019e41f4-832d-7d38-bc97-0cae7fc3b0c4" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_019e41f4-832d-7592-b1c7-fc64d4a2b8fe" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_019e41f4-832d-7592-b1c7-fc64d4a2b8fe_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_019e41f4-832d-7592-b1c7-fc64d4a2b8fe" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_019e41f4-832d-7592-b1c7-fc64d4a2b8fe_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_019e41f4-832d-7ec8-87c7-6b9bd02807f4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_019e41f4-832d-7592-b1c7-fc64d4a2b8fe" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_019e41f4-832d-7ec8-87c7-6b9bd02807f4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SecuritiesSoldUnderAgreementsToRepurchaseMember_019e41f4-832d-7b8d-b73f-1754d396147c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SecuritiesSoldUnderAgreementsToRepurchaseMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_019e41f4-832d-7ec8-87c7-6b9bd02807f4" xlink:to="loc_us-gaap_SecuritiesSoldUnderAgreementsToRepurchaseMember_019e41f4-832d-7b8d-b73f-1754d396147c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_SubordinatedDebenturesAndTermLoansMember_019e41f4-832d-7ff5-a647-7abc8927e14d" xlink:href="frme-20260630.xsd#frme_SubordinatedDebenturesAndTermLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_019e41f4-832d-7ec8-87c7-6b9bd02807f4" xlink:to="loc_frme_SubordinatedDebenturesAndTermLoansMember_019e41f4-832d-7ff5-a647-7abc8927e14d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubordinatedDebtMember_019e41f4-832d-7087-85c7-e67d91839de8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubordinatedDebtMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_019e41f4-832d-7ec8-87c7-6b9bd02807f4" xlink:to="loc_us-gaap_SubordinatedDebtMember_019e41f4-832d-7087-85c7-e67d91839de8" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SecuredDebtMember_019e41f4-832d-76d8-add6-0ff77d3779c9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SecuredDebtMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_019e41f4-832d-7ec8-87c7-6b9bd02807f4" xlink:to="loc_us-gaap_SecuredDebtMember_019e41f4-832d-76d8-add6-0ff77d3779c9" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_019e41f4-832d-768d-9206-26aec7844bee" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_019e41f4-832d-7d38-bc97-0cae7fc3b0c4" xlink:to="loc_srt_RangeAxis_019e41f4-832d-768d-9206-26aec7844bee" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_019e41f4-832d-768d-9206-26aec7844bee_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_019e41f4-832d-768d-9206-26aec7844bee" xlink:to="loc_srt_RangeMember_019e41f4-832d-768d-9206-26aec7844bee_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_019e41f4-832d-7f6d-b1c6-c1d18619843c" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_019e41f4-832d-768d-9206-26aec7844bee" xlink:to="loc_srt_RangeMember_019e41f4-832d-7f6d-b1c6-c1d18619843c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_019e41f4-832d-7e2b-bb39-10f6c773d1ac" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_019e41f4-832d-7f6d-b1c6-c1d18619843c" xlink:to="loc_srt_MinimumMember_019e41f4-832d-7e2b-bb39-10f6c773d1ac" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_019e41f4-832d-7344-ad50-642de7f34a4b" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_019e41f4-832d-7f6d-b1c6-c1d18619843c" xlink:to="loc_srt_MaximumMember_019e41f4-832d-7344-ad50-642de7f34a4b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FederalHomeLoanBankAdvancesOptionAxis_019e41f4-832d-7b96-9231-7dd4d65684ea" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FederalHomeLoanBankAdvancesOptionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_019e41f4-832d-7d38-bc97-0cae7fc3b0c4" xlink:to="loc_us-gaap_FederalHomeLoanBankAdvancesOptionAxis_019e41f4-832d-7b96-9231-7dd4d65684ea" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FederalHomeLoanBankAdvancesOptionDomain_019e41f4-832d-7b96-9231-7dd4d65684ea_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FederalHomeLoanBankAdvancesOptionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FederalHomeLoanBankAdvancesOptionAxis_019e41f4-832d-7b96-9231-7dd4d65684ea" xlink:to="loc_us-gaap_FederalHomeLoanBankAdvancesOptionDomain_019e41f4-832d-7b96-9231-7dd4d65684ea_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FederalHomeLoanBankAdvancesOptionDomain_019e41f4-832d-73e7-9f47-e8a14e6907bb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FederalHomeLoanBankAdvancesOptionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FederalHomeLoanBankAdvancesOptionAxis_019e41f4-832d-7b96-9231-7dd4d65684ea" xlink:to="loc_us-gaap_FederalHomeLoanBankAdvancesOptionDomain_019e41f4-832d-73e7-9f47-e8a14e6907bb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FederalHomeLoanBankAdvancesPutableOptionMember_019e41f4-832d-7915-8147-fa318f6886c1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FederalHomeLoanBankAdvancesPutableOptionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FederalHomeLoanBankAdvancesOptionDomain_019e41f4-832d-73e7-9f47-e8a14e6907bb" xlink:to="loc_us-gaap_FederalHomeLoanBankAdvancesPutableOptionMember_019e41f4-832d-7915-8147-fa318f6886c1" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_LegalEntityAxis_019e41f4-832d-7377-88b4-f9a1298d1366" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_LegalEntityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_019e41f4-832d-7d38-bc97-0cae7fc3b0c4" xlink:to="loc_dei_LegalEntityAxis_019e41f4-832d-7377-88b4-f9a1298d1366" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_019e41f4-832d-7377-88b4-f9a1298d1366_default" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_019e41f4-832d-7377-88b4-f9a1298d1366" xlink:to="loc_dei_EntityDomain_019e41f4-832d-7377-88b4-f9a1298d1366_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_019e41f4-832d-709f-bd9a-846cb6f1cfc2" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_019e41f4-832d-7377-88b4-f9a1298d1366" xlink:to="loc_dei_EntityDomain_019e41f4-832d-709f-bd9a-846cb6f1cfc2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_FirstMerchantCapitalTrustIiMember_019e41f4-832d-781b-9388-c27218172b9f" xlink:href="frme-20260630.xsd#frme_FirstMerchantCapitalTrustIiMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_019e41f4-832d-709f-bd9a-846cb6f1cfc2" xlink:to="loc_frme_FirstMerchantCapitalTrustIiMember_019e41f4-832d-781b-9388-c27218172b9f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_AmerianaCapitalTrustIMember_019e41f4-832d-72aa-beb2-f41ea3b5e969" xlink:href="frme-20260630.xsd#frme_AmerianaCapitalTrustIMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_019e41f4-832d-709f-bd9a-846cb6f1cfc2" xlink:to="loc_frme_AmerianaCapitalTrustIMember_019e41f4-832d-72aa-beb2-f41ea3b5e969" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_019e41f4-832d-799c-a8d1-66ba8ef220c9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_019e41f4-832d-7d38-bc97-0cae7fc3b0c4" xlink:to="loc_us-gaap_DebtInstrumentAxis_019e41f4-832d-799c-a8d1-66ba8ef220c9" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_019e41f4-832d-799c-a8d1-66ba8ef220c9_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_019e41f4-832d-799c-a8d1-66ba8ef220c9" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_019e41f4-832d-799c-a8d1-66ba8ef220c9_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_019e41f4-832d-76f4-b4d8-74fcd19ba750" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_019e41f4-832d-799c-a8d1-66ba8ef220c9" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_019e41f4-832d-76f4-b4d8-74fcd19ba750" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_FirstSavingsSubordinatedNotesMember_019e41f4-832d-73e5-972f-e81932184dec" xlink:href="frme-20260630.xsd#frme_FirstSavingsSubordinatedNotesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_019e41f4-832d-76f4-b4d8-74fcd19ba750" xlink:to="loc_frme_FirstSavingsSubordinatedNotesMember_019e41f4-832d-73e5-972f-e81932184dec" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_U.S.BankN.ACreditAgreementMember_019e41f4-832d-7462-9656-6512c08d30a9" xlink:href="frme-20260630.xsd#frme_U.S.BankN.ACreditAgreementMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_019e41f4-832d-76f4-b4d8-74fcd19ba750" xlink:to="loc_frme_U.S.BankN.ACreditAgreementMember_019e41f4-832d-7462-9656-6512c08d30a9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_019e41f4-832d-74d0-975a-f774b8a2675f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessAcquisitionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_019e41f4-832d-7d38-bc97-0cae7fc3b0c4" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_019e41f4-832d-74d0-975a-f774b8a2675f" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_019e41f4-832d-74d0-975a-f774b8a2675f_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_019e41f4-832d-74d0-975a-f774b8a2675f" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_019e41f4-832d-74d0-975a-f774b8a2675f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_019e41f4-832d-7e84-a8f9-9259eb23b6e3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_019e41f4-832d-74d0-975a-f774b8a2675f" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_019e41f4-832d-7e84-a8f9-9259eb23b6e3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_LevelOneBancorpIncMember_019e41f4-832d-72b9-8b5a-385b4ed34c2c" xlink:href="frme-20260630.xsd#frme_LevelOneBancorpIncMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_019e41f4-832d-7e84-a8f9-9259eb23b6e3" xlink:to="loc_frme_LevelOneBancorpIncMember_019e41f4-832d-72b9-8b5a-385b4ed34c2c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityAxis_019e41f4-832d-7adf-bfd6-1e1dd68674ef" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CreditFacilityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_019e41f4-832d-7d38-bc97-0cae7fc3b0c4" xlink:to="loc_us-gaap_CreditFacilityAxis_019e41f4-832d-7adf-bfd6-1e1dd68674ef" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityDomain_019e41f4-832d-7adf-bfd6-1e1dd68674ef_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CreditFacilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CreditFacilityAxis_019e41f4-832d-7adf-bfd6-1e1dd68674ef" xlink:to="loc_us-gaap_CreditFacilityDomain_019e41f4-832d-7adf-bfd6-1e1dd68674ef_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityDomain_019e41f4-832d-778b-bf25-85a3f9c44102" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CreditFacilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CreditFacilityAxis_019e41f4-832d-7adf-bfd6-1e1dd68674ef" xlink:to="loc_us-gaap_CreditFacilityDomain_019e41f4-832d-778b-bf25-85a3f9c44102" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditMember_019e41f4-832d-7b12-888c-a668b8fea3d4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LineOfCreditMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_019e41f4-832d-778b-bf25-85a3f9c44102" xlink:to="loc_us-gaap_LineOfCreditMember_019e41f4-832d-7b12-888c-a668b8fea3d4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShorttermDebtMaximumAmountOutstandingDuringPeriod_019e41f4-832d-78db-8cea-cda632ef72dd" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShorttermDebtMaximumAmountOutstandingDuringPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019e41f4-832d-7476-9b32-520717e4379d" xlink:to="loc_us-gaap_ShorttermDebtMaximumAmountOutstandingDuringPeriod_019e41f4-832d-78db-8cea-cda632ef72dd" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShorttermDebtAverageOutstandingAmount_019e41f4-832d-7afe-9ac0-9bb8df04fb23" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShorttermDebtAverageOutstandingAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019e41f4-832d-7476-9b32-520717e4379d" xlink:to="loc_us-gaap_ShorttermDebtAverageOutstandingAmount_019e41f4-832d-7afe-9ac0-9bb8df04fb23" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FederalHomeLoanBankAdvancesBranchOfFHLBBankInterestRate_019e41f4-832d-740e-b42a-f0a0216df175" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FederalHomeLoanBankAdvancesBranchOfFHLBBankInterestRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019e41f4-832d-7476-9b32-520717e4379d" xlink:to="loc_us-gaap_FederalHomeLoanBankAdvancesBranchOfFHLBBankInterestRate_019e41f4-832d-740e-b42a-f0a0216df175" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentUnusedBorrowingCapacityAmount_019e41f4-832d-7fff-920c-dc67abd1e983" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentUnusedBorrowingCapacityAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019e41f4-832d-7476-9b32-520717e4379d" xlink:to="loc_us-gaap_DebtInstrumentUnusedBorrowingCapacityAmount_019e41f4-832d-7fff-920c-dc67abd1e983" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdvancesFromFederalHomeLoanBanks_019e41f4-832d-7599-8913-79f1f11dd844" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AdvancesFromFederalHomeLoanBanks"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019e41f4-832d-7476-9b32-520717e4379d" xlink:to="loc_us-gaap_AdvancesFromFederalHomeLoanBanks_019e41f4-832d-7599-8913-79f1f11dd844" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebt_019e41f4-832d-7717-a838-8367953bb324" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongTermDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019e41f4-832d-7476-9b32-520717e4379d" xlink:to="loc_us-gaap_LongTermDebt_019e41f4-832d-7717-a838-8367953bb324" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentFaceAmount_019e41f4-832d-75a4-910d-bbe781e83afe" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentFaceAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019e41f4-832d-7476-9b32-520717e4379d" xlink:to="loc_us-gaap_DebtInstrumentFaceAmount_019e41f4-832d-75a4-910d-bbe781e83afe" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_019e41f4-832d-71e8-9426-4e5323587ce8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentBasisSpreadOnVariableRate1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019e41f4-832d-7476-9b32-520717e4379d" xlink:to="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_019e41f4-832d-71e8-9426-4e5323587ce8" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentInterestRateDuringPeriod_019e41f4-832d-790c-9665-cc764781eb1e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentInterestRateDuringPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019e41f4-832d-7476-9b32-520717e4379d" xlink:to="loc_us-gaap_DebtInstrumentInterestRateDuringPeriod_019e41f4-832d-790c-9665-cc764781eb1e" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_019e41f4-832d-79c5-919e-fb3e887097c0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019e41f4-832d-7476-9b32-520717e4379d" xlink:to="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_019e41f4-832d-79c5-919e-fb3e887097c0" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCredit_019e41f4-832d-7b9a-b7da-73d4353b5ca1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LineOfCredit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019e41f4-832d-7476-9b32-520717e4379d" xlink:to="loc_us-gaap_LineOfCredit_019e41f4-832d-7b9a-b7da-73d4353b5ca1" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_019e41f4-832d-7d57-9507-1d29b9c6c64a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019e41f4-832d-7476-9b32-520717e4379d" xlink:to="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_019e41f4-832d-7d57-9507-1d29b9c6c64a" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityCommitmentFeePercentage_019e41f4-832d-7c06-bb5b-c3f08588e132" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LineOfCreditFacilityCommitmentFeePercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019e41f4-832d-7476-9b32-520717e4379d" xlink:to="loc_us-gaap_LineOfCreditFacilityCommitmentFeePercentage_019e41f4-832d-7c06-bb5b-c3f08588e132" xlink:type="arc" order="12"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.firstmerchants.com/role/BORROWINGSSummaryofCollateralPledgedforRepurchaseAgreementsDetails" xlink:type="simple" xlink:href="frme-20260630.xsd#BORROWINGSSummaryofCollateralPledgedforRepurchaseAgreementsDetails"/>
  <link:definitionLink xlink:role="http://www.firstmerchants.com/role/BORROWINGSSummaryofCollateralPledgedforRepurchaseAgreementsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsSoldUnderAgreementsToRepurchaseLineItems_019e41f4-832d-7c72-b802-9568f9a9798e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetsSoldUnderAgreementsToRepurchaseLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAssetsSoldUnderAgreementsToRepurchaseTable_019e41f4-832d-72e7-bc7c-a8db761f265f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfAssetsSoldUnderAgreementsToRepurchaseTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_AssetsSoldUnderAgreementsToRepurchaseLineItems_019e41f4-832d-7c72-b802-9568f9a9798e" xlink:to="loc_us-gaap_ScheduleOfAssetsSoldUnderAgreementsToRepurchaseTable_019e41f4-832d-72e7-bc7c-a8db761f265f" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsSoldUnderAgreementsToRepurchaseAxis_019e41f4-832d-7528-a569-169e3298125f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetsSoldUnderAgreementsToRepurchaseAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAssetsSoldUnderAgreementsToRepurchaseTable_019e41f4-832d-72e7-bc7c-a8db761f265f" xlink:to="loc_us-gaap_AssetsSoldUnderAgreementsToRepurchaseAxis_019e41f4-832d-7528-a569-169e3298125f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsSoldUnderAgreementsToRepurchaseTypeDomain_019e41f4-832d-7528-a569-169e3298125f_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetsSoldUnderAgreementsToRepurchaseTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AssetsSoldUnderAgreementsToRepurchaseAxis_019e41f4-832d-7528-a569-169e3298125f" xlink:to="loc_us-gaap_AssetsSoldUnderAgreementsToRepurchaseTypeDomain_019e41f4-832d-7528-a569-169e3298125f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsSoldUnderAgreementsToRepurchaseTypeDomain_019e41f4-832d-7fc4-8020-35a2d06a57af" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetsSoldUnderAgreementsToRepurchaseTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AssetsSoldUnderAgreementsToRepurchaseAxis_019e41f4-832d-7528-a569-169e3298125f" xlink:to="loc_us-gaap_AssetsSoldUnderAgreementsToRepurchaseTypeDomain_019e41f4-832d-7fc4-8020-35a2d06a57af" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_USGovernmentSponsoredEnterprisesDebtSecuritiesMember_019e41f4-832d-7658-9bb3-1f9da1dd67ce" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_USGovernmentSponsoredEnterprisesDebtSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsSoldUnderAgreementsToRepurchaseTypeDomain_019e41f4-832d-7fc4-8020-35a2d06a57af" xlink:to="loc_us-gaap_USGovernmentSponsoredEnterprisesDebtSecuritiesMember_019e41f4-832d-7658-9bb3-1f9da1dd67ce" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsSoldUnderAgreementsToRepurchaseMaturityPeriodsAxis_019e41f4-832d-7105-b626-6e5d90a94684" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetsSoldUnderAgreementsToRepurchaseMaturityPeriodsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAssetsSoldUnderAgreementsToRepurchaseTable_019e41f4-832d-72e7-bc7c-a8db761f265f" xlink:to="loc_us-gaap_AssetsSoldUnderAgreementsToRepurchaseMaturityPeriodsAxis_019e41f4-832d-7105-b626-6e5d90a94684" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsSoldUnderAgreementsToRepurchaseMaturityPeriodDomain_019e41f4-832d-7105-b626-6e5d90a94684_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetsSoldUnderAgreementsToRepurchaseMaturityPeriodDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AssetsSoldUnderAgreementsToRepurchaseMaturityPeriodsAxis_019e41f4-832d-7105-b626-6e5d90a94684" xlink:to="loc_us-gaap_AssetsSoldUnderAgreementsToRepurchaseMaturityPeriodDomain_019e41f4-832d-7105-b626-6e5d90a94684_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsSoldUnderAgreementsToRepurchaseMaturityPeriodDomain_019e41f4-832d-7a38-b654-1d4278973659" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetsSoldUnderAgreementsToRepurchaseMaturityPeriodDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AssetsSoldUnderAgreementsToRepurchaseMaturityPeriodsAxis_019e41f4-832d-7105-b626-6e5d90a94684" xlink:to="loc_us-gaap_AssetsSoldUnderAgreementsToRepurchaseMaturityPeriodDomain_019e41f4-832d-7a38-b654-1d4278973659" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MaturityOvernightMember_019e41f4-832d-7df0-ac67-953646ed0aa7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_MaturityOvernightMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsSoldUnderAgreementsToRepurchaseMaturityPeriodDomain_019e41f4-832d-7a38-b654-1d4278973659" xlink:to="loc_us-gaap_MaturityOvernightMember_019e41f4-832d-7df0-ac67-953646ed0aa7" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MaturityUpTo30DaysMember_019e41f4-832d-7379-9569-b3fc377706db" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_MaturityUpTo30DaysMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsSoldUnderAgreementsToRepurchaseMaturityPeriodDomain_019e41f4-832d-7a38-b654-1d4278973659" xlink:to="loc_us-gaap_MaturityUpTo30DaysMember_019e41f4-832d-7379-9569-b3fc377706db" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Maturity30To90DaysMember_019e41f4-832d-7cb2-95d0-8b34724e2345" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_Maturity30To90DaysMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsSoldUnderAgreementsToRepurchaseMaturityPeriodDomain_019e41f4-832d-7a38-b654-1d4278973659" xlink:to="loc_us-gaap_Maturity30To90DaysMember_019e41f4-832d-7cb2-95d0-8b34724e2345" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MaturityOver90DaysMember_019e41f4-832d-730a-86f7-7f1290deaae8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_MaturityOver90DaysMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsSoldUnderAgreementsToRepurchaseMaturityPeriodDomain_019e41f4-832d-7a38-b654-1d4278973659" xlink:to="loc_us-gaap_MaturityOver90DaysMember_019e41f4-832d-730a-86f7-7f1290deaae8" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SecuredDebtRepurchaseAgreements_019e41f4-832d-7102-b911-f691ec8b9807" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SecuredDebtRepurchaseAgreements"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsSoldUnderAgreementsToRepurchaseLineItems_019e41f4-832d-7c72-b802-9568f9a9798e" xlink:to="loc_us-gaap_SecuredDebtRepurchaseAgreements_019e41f4-832d-7102-b911-f691ec8b9807" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.firstmerchants.com/role/BORROWINGSSummaryofContractualMaturitiesofBorrowingsDetails" xlink:type="simple" xlink:href="frme-20260630.xsd#BORROWINGSSummaryofContractualMaturitiesofBorrowingsDetails"/>
  <link:definitionLink xlink:role="http://www.firstmerchants.com/role/BORROWINGSSummaryofContractualMaturitiesofBorrowingsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentLineItems_019e41f4-832d-76e9-b824-ae739b70931b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTable_019e41f4-832d-7c48-876d-e275a4e17251" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019e41f4-832d-76e9-b824-ae739b70931b" xlink:to="loc_us-gaap_DebtInstrumentTable_019e41f4-832d-7c48-876d-e275a4e17251" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_019e41f4-832d-71d8-86fc-7ba6c50f00c3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_019e41f4-832d-7c48-876d-e275a4e17251" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_019e41f4-832d-71d8-86fc-7ba6c50f00c3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_019e41f4-832d-71d8-86fc-7ba6c50f00c3_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_019e41f4-832d-71d8-86fc-7ba6c50f00c3" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_019e41f4-832d-71d8-86fc-7ba6c50f00c3_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_019e41f4-832d-79f8-a496-975ff6a577ea" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_019e41f4-832d-71d8-86fc-7ba6c50f00c3" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_019e41f4-832d-79f8-a496-975ff6a577ea" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SecuritiesSoldUnderAgreementsToRepurchaseMember_019e41f4-832d-76ad-85ac-e19a83abddf7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SecuritiesSoldUnderAgreementsToRepurchaseMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_019e41f4-832d-79f8-a496-975ff6a577ea" xlink:to="loc_us-gaap_SecuritiesSoldUnderAgreementsToRepurchaseMember_019e41f4-832d-76ad-85ac-e19a83abddf7" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FederalHomeLoanBankAdvancesMember_019e41f4-832d-7151-ba2e-afb4342532c3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FederalHomeLoanBankAdvancesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_019e41f4-832d-79f8-a496-975ff6a577ea" xlink:to="loc_us-gaap_FederalHomeLoanBankAdvancesMember_019e41f4-832d-7151-ba2e-afb4342532c3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_SubordinatedDebenturesAndTermLoansMember_019e41f4-832d-7897-9e29-7e2ffcfeabb5" xlink:href="frme-20260630.xsd#frme_SubordinatedDebenturesAndTermLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_019e41f4-832d-79f8-a496-975ff6a577ea" xlink:to="loc_frme_SubordinatedDebenturesAndTermLoansMember_019e41f4-832d-7897-9e29-7e2ffcfeabb5" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtByMaturityAbstract_019e41f4-832d-7f6b-ae39-8666822dc132" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongTermDebtByMaturityAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019e41f4-832d-76e9-b824-ae739b70931b" xlink:to="loc_us-gaap_LongTermDebtByMaturityAbstract_019e41f4-832d-7f6b-ae39-8666822dc132" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalRemainderOfFiscalYear_019e41f4-832d-7db8-8f22-a3974eb4a6ae" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalRemainderOfFiscalYear"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongTermDebtByMaturityAbstract_019e41f4-832d-7f6b-ae39-8666822dc132" xlink:to="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalRemainderOfFiscalYear_019e41f4-832d-7db8-8f22-a3974eb4a6ae" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths_019e41f4-832d-75bb-8b49-a3f8549c05f4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongTermDebtByMaturityAbstract_019e41f4-832d-7f6b-ae39-8666822dc132" xlink:to="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths_019e41f4-832d-75bb-8b49-a3f8549c05f4" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo_019e41f4-832d-7590-9c33-d76aaab60c2c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongTermDebtByMaturityAbstract_019e41f4-832d-7f6b-ae39-8666822dc132" xlink:to="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo_019e41f4-832d-7590-9c33-d76aaab60c2c" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree_019e41f4-832d-7223-aea3-04eb27677875" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongTermDebtByMaturityAbstract_019e41f4-832d-7f6b-ae39-8666822dc132" xlink:to="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree_019e41f4-832d-7223-aea3-04eb27677875" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour_019e41f4-832d-74ad-93b1-8218be0e0370" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongTermDebtByMaturityAbstract_019e41f4-832d-7f6b-ae39-8666822dc132" xlink:to="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour_019e41f4-832d-74ad-93b1-8218be0e0370" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_LongTermDebtMaturityAfterYearFour_019e41f4-832d-7048-9399-c1c4e54280e6" xlink:href="frme-20260630.xsd#frme_LongTermDebtMaturityAfterYearFour"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongTermDebtByMaturityAbstract_019e41f4-832d-7f6b-ae39-8666822dc132" xlink:to="loc_frme_LongTermDebtMaturityAfterYearFour_019e41f4-832d-7048-9399-c1c4e54280e6" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilitiesLongTermDebtFairValueAdjustment_019e41f4-832d-7bbc-815a-f7230fa11321" xlink:href="frme-20260630.xsd#frme_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilitiesLongTermDebtFairValueAdjustment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongTermDebtByMaturityAbstract_019e41f4-832d-7f6b-ae39-8666822dc132" xlink:to="loc_frme_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilitiesLongTermDebtFairValueAdjustment_019e41f4-832d-7bbc-815a-f7230fa11321" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebt_019e41f4-832d-7ed2-8a95-77bf58c60a60" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongTermDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongTermDebtByMaturityAbstract_019e41f4-832d-7f6b-ae39-8666822dc132" xlink:to="loc_us-gaap_LongTermDebt_019e41f4-832d-7ed2-8a95-77bf58c60a60" xlink:type="arc" order="8"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.firstmerchants.com/role/ACCUMULATEDOTHERCOMPREHENSIVELOSSSummaryofAccumulatedOtherComprehensiveIncomeLossDetails" xlink:type="simple" xlink:href="frme-20260630.xsd#ACCUMULATEDOTHERCOMPREHENSIVELOSSSummaryofAccumulatedOtherComprehensiveIncomeLossDetails"/>
  <link:definitionLink xlink:role="http://www.firstmerchants.com/role/ACCUMULATEDOTHERCOMPREHENSIVELOSSSummaryofAccumulatedOtherComprehensiveIncomeLossDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_019e41f4-832d-77de-8ede-aa65cf7d38dd" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_019e41f4-832d-7a9c-9a8f-c320c0b08d9d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_019e41f4-832d-77de-8ede-aa65cf7d38dd" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_019e41f4-832d-7a9c-9a8f-c320c0b08d9d" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_019e41f4-832d-7291-9042-f578c7a8f895" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_019e41f4-832d-7a9c-9a8f-c320c0b08d9d" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_019e41f4-832d-7291-9042-f578c7a8f895" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_019e41f4-832d-7291-9042-f578c7a8f895_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_019e41f4-832d-7291-9042-f578c7a8f895" xlink:to="loc_us-gaap_EquityComponentDomain_019e41f4-832d-7291-9042-f578c7a8f895_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_019e41f4-832d-73c3-b0e7-c87938dda81c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_019e41f4-832d-7291-9042-f578c7a8f895" xlink:to="loc_us-gaap_EquityComponentDomain_019e41f4-832d-73c3-b0e7-c87938dda81c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_019e41f4-832d-70cb-b53a-88848e035368" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_019e41f4-832d-73c3-b0e7-c87938dda81c" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_019e41f4-832d-70cb-b53a-88848e035368" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedNetUnrealizedInvestmentGainLossMember_019e41f4-832d-7cca-84cc-cd26810f36d2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccumulatedNetUnrealizedInvestmentGainLossMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_019e41f4-832d-70cb-b53a-88848e035368" xlink:to="loc_us-gaap_AccumulatedNetUnrealizedInvestmentGainLossMember_019e41f4-832d-7cca-84cc-cd26810f36d2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember_019e41f4-832d-791f-a540-f266b836ce03" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_019e41f4-832d-70cb-b53a-88848e035368" xlink:to="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember_019e41f4-832d-791f-a540-f266b836ce03" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AOCIAttributableToParentNetOfTaxRollForward_019e41f4-832d-721f-96a5-5516e958fb8a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AOCIAttributableToParentNetOfTaxRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_019e41f4-832d-77de-8ede-aa65cf7d38dd" xlink:to="loc_us-gaap_AOCIAttributableToParentNetOfTaxRollForward_019e41f4-832d-721f-96a5-5516e958fb8a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_019e41f4-832d-71f8-9b07-d351578965a6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockholdersEquity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AOCIAttributableToParentNetOfTaxRollForward_019e41f4-832d-721f-96a5-5516e958fb8a" xlink:to="loc_us-gaap_StockholdersEquity_019e41f4-832d-71f8-9b07-d351578965a6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OciBeforeReclassificationsNetOfTaxAttributableToParent_019e41f4-832d-7ead-8e50-4de6870d10ff" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OciBeforeReclassificationsNetOfTaxAttributableToParent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AOCIAttributableToParentNetOfTaxRollForward_019e41f4-832d-721f-96a5-5516e958fb8a" xlink:to="loc_us-gaap_OciBeforeReclassificationsNetOfTaxAttributableToParent_019e41f4-832d-7ead-8e50-4de6870d10ff" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationFromAociCurrentPeriodNetOfTaxAttributableToParent_019e41f4-832d-7034-96ba-57144a4a9bd2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ReclassificationFromAociCurrentPeriodNetOfTaxAttributableToParent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AOCIAttributableToParentNetOfTaxRollForward_019e41f4-832d-721f-96a5-5516e958fb8a" xlink:to="loc_us-gaap_ReclassificationFromAociCurrentPeriodNetOfTaxAttributableToParent_019e41f4-832d-7034-96ba-57144a4a9bd2" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_019e41f4-832d-749a-8021-2a762cb12937" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AOCIAttributableToParentNetOfTaxRollForward_019e41f4-832d-721f-96a5-5516e958fb8a" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_019e41f4-832d-749a-8021-2a762cb12937" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_019e41f4-832d-77c8-8be2-09f50c7ea983" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockholdersEquity"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.firstmerchants.com/role/ACCUMULATEDOTHERCOMPREHENSIVELOSSSummaryofReclassificationoutofAccumulatedOtherComprehensiveIncomeLossDetails" xlink:type="simple" xlink:href="frme-20260630.xsd#ACCUMULATEDOTHERCOMPREHENSIVELOSSSummaryofReclassificationoutofAccumulatedOtherComprehensiveIncomeLossDetails"/>
  <link:definitionLink xlink:role="http://www.firstmerchants.com/role/ACCUMULATEDOTHERCOMPREHENSIVELOSSSummaryofReclassificationoutofAccumulatedOtherComprehensiveIncomeLossDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationAdjustmentOutOfAccumulatedOtherComprehensiveIncomeLineItems_019e41f4-832d-7872-b94f-1d8d18e8a805" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ReclassificationAdjustmentOutOfAccumulatedOtherComprehensiveIncomeLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeTable_019e41f4-832d-7857-a30f-99a088ffe7c4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ReclassificationAdjustmentOutOfAccumulatedOtherComprehensiveIncomeLineItems_019e41f4-832d-7872-b94f-1d8d18e8a805" xlink:to="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeTable_019e41f4-832d-7857-a30f-99a088ffe7c4" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeAxis_019e41f4-832d-7c74-aadc-6dd63cb00d34" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeTable_019e41f4-832d-7857-a30f-99a088ffe7c4" xlink:to="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeAxis_019e41f4-832d-7c74-aadc-6dd63cb00d34" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain_019e41f4-832d-7c74-aadc-6dd63cb00d34_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeAxis_019e41f4-832d-7c74-aadc-6dd63cb00d34" xlink:to="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain_019e41f4-832d-7c74-aadc-6dd63cb00d34_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain_019e41f4-832d-7448-bf1b-2c11eeb68b7c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeAxis_019e41f4-832d-7c74-aadc-6dd63cb00d34" xlink:to="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain_019e41f4-832d-7448-bf1b-2c11eeb68b7c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeMember_019e41f4-832d-7699-b522-265e91ca5548" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain_019e41f4-832d-7448-bf1b-2c11eeb68b7c" xlink:to="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeMember_019e41f4-832d-7699-b522-265e91ca5548" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_019e41f4-832d-7889-b0eb-21d1b440b4e1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeTable_019e41f4-832d-7857-a30f-99a088ffe7c4" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_019e41f4-832d-7889-b0eb-21d1b440b4e1" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_019e41f4-832d-7889-b0eb-21d1b440b4e1_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_019e41f4-832d-7889-b0eb-21d1b440b4e1" xlink:to="loc_us-gaap_EquityComponentDomain_019e41f4-832d-7889-b0eb-21d1b440b4e1_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_019e41f4-832d-7be8-a3ab-b5e63e3487f5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_019e41f4-832d-7889-b0eb-21d1b440b4e1" xlink:to="loc_us-gaap_EquityComponentDomain_019e41f4-832d-7be8-a3ab-b5e63e3487f5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedNetUnrealizedInvestmentGainLossMember_019e41f4-832d-740f-8186-87524852bea9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccumulatedNetUnrealizedInvestmentGainLossMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_019e41f4-832d-7be8-a3ab-b5e63e3487f5" xlink:to="loc_us-gaap_AccumulatedNetUnrealizedInvestmentGainLossMember_019e41f4-832d-740f-8186-87524852bea9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleUnrealizedGainLoss_019e41f4-832d-7dcf-84c7-d47d7383eb39" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtSecuritiesAvailableForSaleUnrealizedGainLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReclassificationAdjustmentOutOfAccumulatedOtherComprehensiveIncomeLineItems_019e41f4-832d-7872-b94f-1d8d18e8a805" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleUnrealizedGainLoss_019e41f4-832d-7dcf-84c7-d47d7383eb39" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxExpenseBenefit_019e41f4-832d-71b8-a5a9-dce5106d63cd" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeTaxExpenseBenefit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReclassificationAdjustmentOutOfAccumulatedOtherComprehensiveIncomeLineItems_019e41f4-832d-7872-b94f-1d8d18e8a805" xlink:to="loc_us-gaap_IncomeTaxExpenseBenefit_019e41f4-832d-71b8-a5a9-dce5106d63cd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_019e41f4-832d-7497-abb9-ac5ce7f845aa" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReclassificationAdjustmentOutOfAccumulatedOtherComprehensiveIncomeLineItems_019e41f4-832d-7872-b94f-1d8d18e8a805" xlink:to="loc_us-gaap_NetIncomeLoss_019e41f4-832d-7497-abb9-ac5ce7f845aa" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.firstmerchants.com/role/SHAREBASEDCOMPENSATIONNarrativeDetails" xlink:type="simple" xlink:href="frme-20260630.xsd#SHAREBASEDCOMPENSATIONNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.firstmerchants.com/role/SHAREBASEDCOMPENSATIONNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019e41f4-832d-748b-bc95-7eda660402b0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_019e41f4-832d-7711-9a92-7a9650ec12c5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019e41f4-832d-748b-bc95-7eda660402b0" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_019e41f4-832d-7711-9a92-7a9650ec12c5" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_019e41f4-832d-74f4-8472-2bc32eb3aca3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_019e41f4-832d-7711-9a92-7a9650ec12c5" xlink:to="loc_us-gaap_AwardTypeAxis_019e41f4-832d-74f4-8472-2bc32eb3aca3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019e41f4-832d-74f4-8472-2bc32eb3aca3_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_019e41f4-832d-74f4-8472-2bc32eb3aca3" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019e41f4-832d-74f4-8472-2bc32eb3aca3_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019e41f4-832d-7984-85c8-89a228566929" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_019e41f4-832d-74f4-8472-2bc32eb3aca3" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019e41f4-832d-7984-85c8-89a228566929" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeStockOptionMember_019e41f4-832d-76a7-a800-6fbd718b5c6b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EmployeeStockOptionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019e41f4-832d-7984-85c8-89a228566929" xlink:to="loc_us-gaap_EmployeeStockOptionMember_019e41f4-832d-76a7-a800-6fbd718b5c6b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_RestrictedStockAwardsMember_019e41f4-832d-7420-81c0-49182269c746" xlink:href="frme-20260630.xsd#frme_RestrictedStockAwardsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019e41f4-832d-7984-85c8-89a228566929" xlink:to="loc_frme_RestrictedStockAwardsMember_019e41f4-832d-7420-81c0-49182269c746" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeStockMember_019e41f4-832d-7681-ac20-a9b72d0d3940" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EmployeeStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019e41f4-832d-7984-85c8-89a228566929" xlink:to="loc_us-gaap_EmployeeStockMember_019e41f4-832d-7681-ac20-a9b72d0d3940" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_019e41f4-832d-79c3-8a36-d220980e2ae3" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_019e41f4-832d-7711-9a92-7a9650ec12c5" xlink:to="loc_srt_RangeAxis_019e41f4-832d-79c3-8a36-d220980e2ae3" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_019e41f4-832d-79c3-8a36-d220980e2ae3_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_019e41f4-832d-79c3-8a36-d220980e2ae3" xlink:to="loc_srt_RangeMember_019e41f4-832d-79c3-8a36-d220980e2ae3_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_019e41f4-832d-7b12-9c09-d75be25ce957" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_019e41f4-832d-79c3-8a36-d220980e2ae3" xlink:to="loc_srt_RangeMember_019e41f4-832d-7b12-9c09-d75be25ce957" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_019e41f4-832d-76d9-98eb-2d92b953e446" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_019e41f4-832d-7b12-9c09-d75be25ce957" xlink:to="loc_srt_MinimumMember_019e41f4-832d-76d9-98eb-2d92b953e446" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_019e41f4-832d-7ea0-ba36-9f9fa6946dff" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_019e41f4-832d-7b12-9c09-d75be25ce957" xlink:to="loc_srt_MaximumMember_019e41f4-832d-7ea0-ba36-9f9fa6946dff" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod_019e41f4-832d-78cc-a610-18e754671dea" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019e41f4-832d-748b-bc95-7eda660402b0" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod_019e41f4-832d-78cc-a610-18e754671dea" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardAwardVestingRightsPercentage_019e41f4-832d-77a4-8e02-b61ab2d338c1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardAwardVestingRightsPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019e41f4-832d-748b-bc95-7eda660402b0" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardAwardVestingRightsPercentage_019e41f4-832d-77a4-8e02-b61ab2d338c1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_019e41f4-832d-7419-8546-9f73a1b4bd80" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019e41f4-832d-748b-bc95-7eda660402b0" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_019e41f4-832d-7419-8546-9f73a1b4bd80" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardPurchasePriceOfCommonStockPercent_019e41f4-832d-7506-9717-fdb92abc9643" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardPurchasePriceOfCommonStockPercent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019e41f4-832d-748b-bc95-7eda660402b0" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardPurchasePriceOfCommonStockPercent_019e41f4-832d-7506-9717-fdb92abc9643" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_EmployeeStockPurchasePlanEmployeeContributionAmount_019e41f4-832d-7f81-8837-74f82d43776d" xlink:href="frme-20260630.xsd#frme_EmployeeStockPurchasePlanEmployeeContributionAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019e41f4-832d-748b-bc95-7eda660402b0" xlink:to="loc_frme_EmployeeStockPurchasePlanEmployeeContributionAmount_019e41f4-832d-7f81-8837-74f82d43776d" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedInPeriodFairValue1_019e41f4-832d-7920-baeb-8e5a0971f42c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedInPeriodFairValue1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019e41f4-832d-748b-bc95-7eda660402b0" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedInPeriodFairValue1_019e41f4-832d-7920-baeb-8e5a0971f42c" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedStockOptions_019e41f4-832d-73e1-831b-34bd697d3fde" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedStockOptions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019e41f4-832d-748b-bc95-7eda660402b0" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedStockOptions_019e41f4-832d-73e1-831b-34bd697d3fde" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromStockOptionsExercised_019e41f4-832d-7f8b-86be-2ecf7b30e0c4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProceedsFromStockOptionsExercised"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019e41f4-832d-748b-bc95-7eda660402b0" xlink:to="loc_us-gaap_ProceedsFromStockOptionsExercised_019e41f4-832d-7f8b-86be-2ecf7b30e0c4" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedShareBasedAwardsOtherThanOptions_019e41f4-832d-7fd9-8988-c2f9f2e94954" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedShareBasedAwardsOtherThanOptions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019e41f4-832d-748b-bc95-7eda660402b0" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedShareBasedAwardsOtherThanOptions_019e41f4-832d-7fd9-8988-c2f9f2e94954" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_019e41f4-832d-71c2-a859-3f2a85b7c5ed" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019e41f4-832d-748b-bc95-7eda660402b0" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_019e41f4-832d-71c2-a859-3f2a85b7c5ed" xlink:type="arc" order="9"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.firstmerchants.com/role/SHAREBASEDCOMPENSATIONSummaryofComponentsofShareBasedCompensationAwardsDetails" xlink:type="simple" xlink:href="frme-20260630.xsd#SHAREBASEDCOMPENSATIONSummaryofComponentsofShareBasedCompensationAwardsDetails"/>
  <link:definitionLink xlink:role="http://www.firstmerchants.com/role/SHAREBASEDCOMPENSATIONSummaryofComponentsofShareBasedCompensationAwardsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019e41f4-832d-7d60-86b8-83e80cd756df" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_019e41f4-832d-71c1-83e3-f5247637912a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019e41f4-832d-7d60-86b8-83e80cd756df" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_019e41f4-832d-71c1-83e3-f5247637912a" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_019e41f4-832d-762f-b293-70ad72228fa8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_019e41f4-832d-71c1-83e3-f5247637912a" xlink:to="loc_us-gaap_AwardTypeAxis_019e41f4-832d-762f-b293-70ad72228fa8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019e41f4-832d-762f-b293-70ad72228fa8_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_019e41f4-832d-762f-b293-70ad72228fa8" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019e41f4-832d-762f-b293-70ad72228fa8_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019e41f4-832d-710f-8b27-efe4650b62ab" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_019e41f4-832d-762f-b293-70ad72228fa8" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019e41f4-832d-710f-8b27-efe4650b62ab" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_StockOptionsAndEmployeeStockPurchasePlanMember_019e41f4-832d-7d08-93ba-57ff0bf36b5a" xlink:href="frme-20260630.xsd#frme_StockOptionsAndEmployeeStockPurchasePlanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019e41f4-832d-710f-8b27-efe4650b62ab" xlink:to="loc_frme_StockOptionsAndEmployeeStockPurchasePlanMember_019e41f4-832d-7d08-93ba-57ff0bf36b5a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_RestrictedStockAwardsMember_019e41f4-832d-7af5-82e2-d6322506540b" xlink:href="frme-20260630.xsd#frme_RestrictedStockAwardsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019e41f4-832d-710f-8b27-efe4650b62ab" xlink:to="loc_frme_RestrictedStockAwardsMember_019e41f4-832d-7af5-82e2-d6322506540b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllocatedShareBasedCompensationExpense_019e41f4-832d-7b31-8d84-53e42088010b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AllocatedShareBasedCompensationExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019e41f4-832d-7d60-86b8-83e80cd756df" xlink:to="loc_us-gaap_AllocatedShareBasedCompensationExpense_019e41f4-832d-7b31-8d84-53e42088010b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense_019e41f4-832d-7d00-9dc6-78457819fac7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019e41f4-832d-7d60-86b8-83e80cd756df" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense_019e41f4-832d-7d00-9dc6-78457819fac7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllocatedShareBasedCompensationExpenseNetOfTax_019e41f4-832d-7e86-9f1e-9960b32f3e03" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AllocatedShareBasedCompensationExpenseNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019e41f4-832d-7d60-86b8-83e80cd756df" xlink:to="loc_us-gaap_AllocatedShareBasedCompensationExpenseNetOfTax_019e41f4-832d-7e86-9f1e-9960b32f3e03" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.firstmerchants.com/role/SHAREBASEDCOMPENSATIONSummaryofUnvestedRSAsOutstandingDetails" xlink:type="simple" xlink:href="frme-20260630.xsd#SHAREBASEDCOMPENSATIONSummaryofUnvestedRSAsOutstandingDetails"/>
  <link:definitionLink xlink:role="http://www.firstmerchants.com/role/SHAREBASEDCOMPENSATIONSummaryofUnvestedRSAsOutstandingDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019e41f4-832d-798c-8da8-2acb2910d2be" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_019e41f4-832d-7ad8-a03f-9a1748a88433" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019e41f4-832d-798c-8da8-2acb2910d2be" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_019e41f4-832d-7ad8-a03f-9a1748a88433" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_019e41f4-832d-7e35-b018-7e01e7de77de" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_019e41f4-832d-7ad8-a03f-9a1748a88433" xlink:to="loc_us-gaap_AwardTypeAxis_019e41f4-832d-7e35-b018-7e01e7de77de" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019e41f4-832d-7e35-b018-7e01e7de77de_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_019e41f4-832d-7e35-b018-7e01e7de77de" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019e41f4-832d-7e35-b018-7e01e7de77de_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019e41f4-832d-7ded-b811-ab7f4f5f7703" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_019e41f4-832d-7e35-b018-7e01e7de77de" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019e41f4-832d-7ded-b811-ab7f4f5f7703" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_frme_RestrictedStockAwardsMember_019e41f4-832d-72f7-bbbf-291e53a4482c" xlink:href="frme-20260630.xsd#frme_RestrictedStockAwardsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019e41f4-832d-7ded-b811-ab7f4f5f7703" xlink:to="loc_frme_RestrictedStockAwardsMember_019e41f4-832d-72f7-bbbf-291e53a4482c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_019e41f4-832d-7c55-99e4-efef2c0ddd5d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019e41f4-832d-798c-8da8-2acb2910d2be" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_019e41f4-832d-7c55-99e4-efef2c0ddd5d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_019e41f4-832d-7dbf-a2a5-6a6aeb753318" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_019e41f4-832d-7c55-99e4-efef2c0ddd5d" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_019e41f4-832d-7dbf-a2a5-6a6aeb753318" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_019e41f4-832d-7a84-9c7a-47d03ba765e9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_019e41f4-832d-7c55-99e4-efef2c0ddd5d" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_019e41f4-832d-7a84-9c7a-47d03ba765e9" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_019e41f4-832d-78ac-93aa-dfae6fd0212b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_019e41f4-832d-7c55-99e4-efef2c0ddd5d" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_019e41f4-832d-78ac-93aa-dfae6fd0212b" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_019e41f4-832d-79ca-92c4-6c4c1c551bf5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_019e41f4-832d-7c55-99e4-efef2c0ddd5d" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_019e41f4-832d-79ca-92c4-6c4c1c551bf5" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_019e41f4-832d-7fed-a56e-ee71ac27f936" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_019e41f4-832d-7f1d-9869-ae75b7d37fc0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019e41f4-832d-798c-8da8-2acb2910d2be" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_019e41f4-832d-7f1d-9869-ae75b7d37fc0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_019e41f4-832d-7ec3-bd5c-1ea929a88713" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_019e41f4-832d-7f1d-9869-ae75b7d37fc0" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_019e41f4-832d-7ec3-bd5c-1ea929a88713" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_019e41f4-832d-7893-ac0d-1e298e8ca987" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_019e41f4-832d-7f1d-9869-ae75b7d37fc0" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_019e41f4-832d-7893-ac0d-1e298e8ca987" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_019e41f4-832d-7cc9-bc7e-5d6735a17c1b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_019e41f4-832d-7f1d-9869-ae75b7d37fc0" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_019e41f4-832d-7cc9-bc7e-5d6735a17c1b" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue_019e41f4-832d-7bd3-9120-e30980ce4d4f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_019e41f4-832d-7f1d-9869-ae75b7d37fc0" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue_019e41f4-832d-7bd3-9120-e30980ce4d4f" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_019e41f4-832d-7a0a-ac20-2677e6ab179a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue"/>
  </link:definitionLink>
</link:linkbase>
