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

<!--XBRL Document Created with the Workiva Platform-->
<!--Copyright 2026 Workiva-->
<!--r:019d0150-62dc-77d7-8e08-eb02e0f3ddfd,g:f3eaf7f7-3af9-473f-bcb1-95e03f216640-->
<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.cat.com/role/CoverPage" xlink:type="simple" xlink:href="cat-20260331.xsd#CoverPage"/>
  <link:definitionLink xlink:role="http://www.cat.com/role/CoverPage" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityInformationLineItems_019d0150-6786-7144-9192-b9f3d2a0465d" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityInformationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntitiesTable_019d0150-6786-7345-a41f-267917023c4a" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntitiesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_dei_EntityInformationLineItems_019d0150-6786-7144-9192-b9f3d2a0465d" xlink:to="loc_dei_EntitiesTable_019d0150-6786-7345-a41f-267917023c4a" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementClassOfStockAxis_019d0150-6786-7bc9-b909-1c848eb7669e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementClassOfStockAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_dei_EntitiesTable_019d0150-6786-7345-a41f-267917023c4a" xlink:to="loc_us-gaap_StatementClassOfStockAxis_019d0150-6786-7bc9-b909-1c848eb7669e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_019d0150-6786-7bc9-b909-1c848eb7669e_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_019d0150-6786-7bc9-b909-1c848eb7669e" xlink:to="loc_us-gaap_ClassOfStockDomain_019d0150-6786-7bc9-b909-1c848eb7669e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_019d0150-6786-75db-b73a-2936aaccf4a0" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_019d0150-6786-7bc9-b909-1c848eb7669e" xlink:to="loc_us-gaap_ClassOfStockDomain_019d0150-6786-75db-b73a-2936aaccf4a0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockMember_019d0150-6786-76fc-8c21-d1f36b042ca0" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CommonStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_019d0150-6786-75db-b73a-2936aaccf4a0" xlink:to="loc_us-gaap_CommonStockMember_019d0150-6786-76fc-8c21-d1f36b042ca0" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_A5.3DebenturesDueSeptember152035Member_019d0150-6786-7274-a65e-de79ebf556b1" xlink:href="cat-20260331.xsd#cat_A5.3DebenturesDueSeptember152035Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_019d0150-6786-75db-b73a-2936aaccf4a0" xlink:to="loc_cat_A5.3DebenturesDueSeptember152035Member_019d0150-6786-7274-a65e-de79ebf556b1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentType_019d0150-6786-7232-ab6d-33684a9dc4fd" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_DocumentType"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019d0150-6786-7144-9192-b9f3d2a0465d" xlink:to="loc_dei_DocumentType_019d0150-6786-7232-ab6d-33684a9dc4fd" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentQuarterlyReport_019d0150-6786-731f-b5c6-7b98b22d9246" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_DocumentQuarterlyReport"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019d0150-6786-7144-9192-b9f3d2a0465d" xlink:to="loc_dei_DocumentQuarterlyReport_019d0150-6786-731f-b5c6-7b98b22d9246" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentPeriodEndDate_019d0150-6786-7dd4-974f-eab382082917" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_DocumentPeriodEndDate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019d0150-6786-7144-9192-b9f3d2a0465d" xlink:to="loc_dei_DocumentPeriodEndDate_019d0150-6786-7dd4-974f-eab382082917" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentTransitionReport_019d0150-6786-71d4-9dde-e7018bf7a94d" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_DocumentTransitionReport"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019d0150-6786-7144-9192-b9f3d2a0465d" xlink:to="loc_dei_DocumentTransitionReport_019d0150-6786-71d4-9dde-e7018bf7a94d" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityFileNumber_019d0150-6786-7570-a9d0-6223ccefc643" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityFileNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019d0150-6786-7144-9192-b9f3d2a0465d" xlink:to="loc_dei_EntityFileNumber_019d0150-6786-7570-a9d0-6223ccefc643" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityRegistrantName_019d0150-6786-702e-b5fd-4826d71445d8" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityRegistrantName"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019d0150-6786-7144-9192-b9f3d2a0465d" xlink:to="loc_dei_EntityRegistrantName_019d0150-6786-702e-b5fd-4826d71445d8" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityIncorporationStateCountryCode_019d0150-6786-75af-9c9f-73a724ebc672" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityIncorporationStateCountryCode"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019d0150-6786-7144-9192-b9f3d2a0465d" xlink:to="loc_dei_EntityIncorporationStateCountryCode_019d0150-6786-75af-9c9f-73a724ebc672" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityTaxIdentificationNumber_019d0150-6786-79b7-a571-fcab314c11e5" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityTaxIdentificationNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019d0150-6786-7144-9192-b9f3d2a0465d" xlink:to="loc_dei_EntityTaxIdentificationNumber_019d0150-6786-79b7-a571-fcab314c11e5" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressAddressLine1_019d0150-6786-7822-a217-bbd8f21075d1" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityAddressAddressLine1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019d0150-6786-7144-9192-b9f3d2a0465d" xlink:to="loc_dei_EntityAddressAddressLine1_019d0150-6786-7822-a217-bbd8f21075d1" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressAddressLine2_019d0150-6786-7edb-82a9-9831d65a4306" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityAddressAddressLine2"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019d0150-6786-7144-9192-b9f3d2a0465d" xlink:to="loc_dei_EntityAddressAddressLine2_019d0150-6786-7edb-82a9-9831d65a4306" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressCityOrTown_019d0150-6786-75da-b3d5-123a255af159" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityAddressCityOrTown"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019d0150-6786-7144-9192-b9f3d2a0465d" xlink:to="loc_dei_EntityAddressCityOrTown_019d0150-6786-75da-b3d5-123a255af159" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressStateOrProvince_019d0150-6786-76e7-9d7b-837b9595c242" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityAddressStateOrProvince"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019d0150-6786-7144-9192-b9f3d2a0465d" xlink:to="loc_dei_EntityAddressStateOrProvince_019d0150-6786-76e7-9d7b-837b9595c242" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressPostalZipCode_019d0150-6786-7663-a2f2-f147303ef2fc" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityAddressPostalZipCode"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019d0150-6786-7144-9192-b9f3d2a0465d" xlink:to="loc_dei_EntityAddressPostalZipCode_019d0150-6786-7663-a2f2-f147303ef2fc" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_CityAreaCode_019d0150-6786-7c6e-9c46-e04b4edc678b" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_CityAreaCode"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019d0150-6786-7144-9192-b9f3d2a0465d" xlink:to="loc_dei_CityAreaCode_019d0150-6786-7c6e-9c46-e04b4edc678b" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_LocalPhoneNumber_019d0150-6786-7eb6-95d6-9c462afa9982" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_LocalPhoneNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019d0150-6786-7144-9192-b9f3d2a0465d" xlink:to="loc_dei_LocalPhoneNumber_019d0150-6786-7eb6-95d6-9c462afa9982" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_Security12bTitle_019d0150-6786-7a2e-988b-b7cf3ebd78d7" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_Security12bTitle"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019d0150-6786-7144-9192-b9f3d2a0465d" xlink:to="loc_dei_Security12bTitle_019d0150-6786-7a2e-988b-b7cf3ebd78d7" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_TradingSymbol_019d0150-6786-7f12-ac12-db2d34d4bd6f" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_TradingSymbol"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019d0150-6786-7144-9192-b9f3d2a0465d" xlink:to="loc_dei_TradingSymbol_019d0150-6786-7f12-ac12-db2d34d4bd6f" xlink:type="arc" order="16"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_SecurityExchangeName_019d0150-6786-71db-94fb-dc2e0efdef41" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_SecurityExchangeName"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019d0150-6786-7144-9192-b9f3d2a0465d" xlink:to="loc_dei_SecurityExchangeName_019d0150-6786-71db-94fb-dc2e0efdef41" xlink:type="arc" order="17"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityCurrentReportingStatus_019d0150-6786-71c0-be98-86b8719b2116" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityCurrentReportingStatus"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019d0150-6786-7144-9192-b9f3d2a0465d" xlink:to="loc_dei_EntityCurrentReportingStatus_019d0150-6786-71c0-be98-86b8719b2116" xlink:type="arc" order="18"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityInteractiveDataCurrent_019d0150-6786-7c2b-9bd6-1c9704fc53a5" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityInteractiveDataCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019d0150-6786-7144-9192-b9f3d2a0465d" xlink:to="loc_dei_EntityInteractiveDataCurrent_019d0150-6786-7c2b-9bd6-1c9704fc53a5" xlink:type="arc" order="19"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityFilerCategory_019d0150-6786-7b37-bb7a-5309d34190f4" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityFilerCategory"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019d0150-6786-7144-9192-b9f3d2a0465d" xlink:to="loc_dei_EntityFilerCategory_019d0150-6786-7b37-bb7a-5309d34190f4" xlink:type="arc" order="20"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntitySmallBusiness_019d0150-6786-76f8-8a62-3e4696da90d4" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntitySmallBusiness"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019d0150-6786-7144-9192-b9f3d2a0465d" xlink:to="loc_dei_EntitySmallBusiness_019d0150-6786-76f8-8a62-3e4696da90d4" xlink:type="arc" order="21"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityEmergingGrowthCompany_019d0150-6786-727c-9e7f-294f1b4bea0d" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityEmergingGrowthCompany"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019d0150-6786-7144-9192-b9f3d2a0465d" xlink:to="loc_dei_EntityEmergingGrowthCompany_019d0150-6786-727c-9e7f-294f1b4bea0d" xlink:type="arc" order="22"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityShellCompany_019d0150-6786-7934-a6db-fa427bd65ecd" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityShellCompany"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019d0150-6786-7144-9192-b9f3d2a0465d" xlink:to="loc_dei_EntityShellCompany_019d0150-6786-7934-a6db-fa427bd65ecd" xlink:type="arc" order="23"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityCommonStockSharesOutstanding_019d0150-6786-75b8-bf91-e7c2b96fd8d8" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityCommonStockSharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019d0150-6786-7144-9192-b9f3d2a0465d" xlink:to="loc_dei_EntityCommonStockSharesOutstanding_019d0150-6786-75b8-bf91-e7c2b96fd8d8" xlink:type="arc" order="24"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityCentralIndexKey_019d0150-6786-79f7-9a7a-bceefe712a01" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityCentralIndexKey"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019d0150-6786-7144-9192-b9f3d2a0465d" xlink:to="loc_dei_EntityCentralIndexKey_019d0150-6786-79f7-9a7a-bceefe712a01" xlink:type="arc" order="25"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_AmendmentFlag_019d0150-6786-7370-94af-fc5bd1975602" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_AmendmentFlag"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019d0150-6786-7144-9192-b9f3d2a0465d" xlink:to="loc_dei_AmendmentFlag_019d0150-6786-7370-94af-fc5bd1975602" xlink:type="arc" order="26"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_CurrentFiscalYearEndDate_019d0150-6786-716f-b722-792b302a4718" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_CurrentFiscalYearEndDate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019d0150-6786-7144-9192-b9f3d2a0465d" xlink:to="loc_dei_CurrentFiscalYearEndDate_019d0150-6786-716f-b722-792b302a4718" xlink:type="arc" order="27"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentFiscalYearFocus_019d0150-6786-7f0a-bd48-b487bb6cf87e" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_DocumentFiscalYearFocus"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019d0150-6786-7144-9192-b9f3d2a0465d" xlink:to="loc_dei_DocumentFiscalYearFocus_019d0150-6786-7f0a-bd48-b487bb6cf87e" xlink:type="arc" order="28"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentFiscalPeriodFocus_019d0150-6786-72ef-9513-1695b1b8ebaf" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_DocumentFiscalPeriodFocus"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019d0150-6786-7144-9192-b9f3d2a0465d" xlink:to="loc_dei_DocumentFiscalPeriodFocus_019d0150-6786-72ef-9513-1695b1b8ebaf" xlink:type="arc" order="29"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.cat.com/role/ConsolidatedStatementofResultsofOperations" xlink:type="simple" xlink:href="cat-20260331.xsd#ConsolidatedStatementofResultsofOperations"/>
  <link:definitionLink xlink:role="http://www.cat.com/role/ConsolidatedStatementofResultsofOperations" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_019d0150-6786-747a-b17f-55e061ea8b84" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_019d0150-6786-7eed-be08-561cbe77e810" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_019d0150-6786-747a-b17f-55e061ea8b84" xlink:to="loc_us-gaap_StatementTable_019d0150-6786-7eed-be08-561cbe77e810" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_019d0150-6786-7ffa-81bd-bcf6207bcb0c" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_ProductOrServiceAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_019d0150-6786-7eed-be08-561cbe77e810" xlink:to="loc_srt_ProductOrServiceAxis_019d0150-6786-7ffa-81bd-bcf6207bcb0c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_019d0150-6786-7ffa-81bd-bcf6207bcb0c_default" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_019d0150-6786-7ffa-81bd-bcf6207bcb0c" xlink:to="loc_srt_ProductsAndServicesDomain_019d0150-6786-7ffa-81bd-bcf6207bcb0c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_019d0150-6786-71db-8be6-76f681540c86" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_019d0150-6786-7ffa-81bd-bcf6207bcb0c" xlink:to="loc_srt_ProductsAndServicesDomain_019d0150-6786-71db-8be6-76f681540c86" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_MachineryPowerEnergyMember_019d0150-6786-7ec9-a9eb-eaf50d95bf32" xlink:href="cat-20260331.xsd#cat_MachineryPowerEnergyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_019d0150-6786-71db-8be6-76f681540c86" xlink:to="loc_cat_MachineryPowerEnergyMember_019d0150-6786-7ec9-a9eb-eaf50d95bf32" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_FinancialProductsMember_019d0150-6786-76c6-8aa6-3ac4ccac6619" xlink:href="cat-20260331.xsd#cat_FinancialProductsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_019d0150-6786-71db-8be6-76f681540c86" xlink:to="loc_cat_FinancialProductsMember_019d0150-6786-76c6-8aa6-3ac4ccac6619" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_AllOtherExcludingFinancialProductsMember_019d0150-6786-7050-8924-6837d5196560" xlink:href="cat-20260331.xsd#cat_AllOtherExcludingFinancialProductsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_019d0150-6786-71db-8be6-76f681540c86" xlink:to="loc_cat_AllOtherExcludingFinancialProductsMember_019d0150-6786-7050-8924-6837d5196560" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenuesAbstract_019d0150-6786-793e-b176-8b62b6a52905" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RevenuesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019d0150-6786-747a-b17f-55e061ea8b84" xlink:to="loc_us-gaap_RevenuesAbstract_019d0150-6786-793e-b176-8b62b6a52905" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Revenues_019d0150-6786-75fe-80cb-dc9d1bfcb1b8" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_Revenues"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenuesAbstract_019d0150-6786-793e-b176-8b62b6a52905" xlink:to="loc_us-gaap_Revenues_019d0150-6786-75fe-80cb-dc9d1bfcb1b8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingExpensesAbstract_019d0150-6786-7e63-b895-b66f66971647" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OperatingExpensesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019d0150-6786-747a-b17f-55e061ea8b84" xlink:to="loc_us-gaap_OperatingExpensesAbstract_019d0150-6786-7e63-b895-b66f66971647" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CostOfRevenue_019d0150-6786-7585-a714-7702d17521ac" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CostOfRevenue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingExpensesAbstract_019d0150-6786-7e63-b895-b66f66971647" xlink:to="loc_us-gaap_CostOfRevenue_019d0150-6786-7585-a714-7702d17521ac" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SellingGeneralAndAdministrativeExpense_019d0150-6786-7b8e-ae24-8814d145450c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SellingGeneralAndAdministrativeExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingExpensesAbstract_019d0150-6786-7e63-b895-b66f66971647" xlink:to="loc_us-gaap_SellingGeneralAndAdministrativeExpense_019d0150-6786-7b8e-ae24-8814d145450c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ResearchAndDevelopmentExpense_019d0150-6786-7c1e-8e1e-eddc34160a62" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ResearchAndDevelopmentExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingExpensesAbstract_019d0150-6786-7e63-b895-b66f66971647" xlink:to="loc_us-gaap_ResearchAndDevelopmentExpense_019d0150-6786-7c1e-8e1e-eddc34160a62" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingInterestExpense_019d0150-6786-74fb-a66e-e7bd700fdffe" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancingInterestExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingExpensesAbstract_019d0150-6786-7e63-b895-b66f66971647" xlink:to="loc_us-gaap_FinancingInterestExpense_019d0150-6786-74fb-a66e-e7bd700fdffe" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherOperatingIncomeExpenseNet_019d0150-6786-767d-928b-48def18c0a75" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherOperatingIncomeExpenseNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingExpensesAbstract_019d0150-6786-7e63-b895-b66f66971647" xlink:to="loc_us-gaap_OtherOperatingIncomeExpenseNet_019d0150-6786-767d-928b-48def18c0a75" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CostsAndExpenses_019d0150-6786-7e1c-8682-825ce701adf1" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CostsAndExpenses"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingExpensesAbstract_019d0150-6786-7e63-b895-b66f66971647" xlink:to="loc_us-gaap_CostsAndExpenses_019d0150-6786-7e1c-8682-825ce701adf1" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingIncomeLoss_019d0150-6786-77cb-95cb-59ce7f7d4477" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OperatingIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019d0150-6786-747a-b17f-55e061ea8b84" xlink:to="loc_us-gaap_OperatingIncomeLoss_019d0150-6786-77cb-95cb-59ce7f7d4477" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestExpenseNonoperating_019d0150-6786-7bfa-8eca-4eca3f226c45" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_InterestExpenseNonoperating"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019d0150-6786-747a-b17f-55e061ea8b84" xlink:to="loc_us-gaap_InterestExpenseNonoperating_019d0150-6786-7bfa-8eca-4eca3f226c45" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherNonoperatingIncomeExpense_019d0150-6786-775b-9f97-2703330345cc" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherNonoperatingIncomeExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019d0150-6786-747a-b17f-55e061ea8b84" xlink:to="loc_us-gaap_OtherNonoperatingIncomeExpense_019d0150-6786-775b-9f97-2703330345cc" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments_019d0150-6786-77e0-b2a2-f123e610f0b4" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019d0150-6786-747a-b17f-55e061ea8b84" xlink:to="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments_019d0150-6786-77e0-b2a2-f123e610f0b4" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxExpenseBenefit_019d0150-6786-7542-91a2-ad3981f7dc6a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeTaxExpenseBenefit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019d0150-6786-747a-b17f-55e061ea8b84" xlink:to="loc_us-gaap_IncomeTaxExpenseBenefit_019d0150-6786-7542-91a2-ad3981f7dc6a" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_ProfitOfConsolidatedCompanies_019d0150-6786-7c6d-99d3-2b1fedb1e9b3" xlink:href="cat-20260331.xsd#cat_ProfitOfConsolidatedCompanies"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019d0150-6786-747a-b17f-55e061ea8b84" xlink:to="loc_cat_ProfitOfConsolidatedCompanies_019d0150-6786-7c6d-99d3-2b1fedb1e9b3" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromEquityMethodInvestments_019d0150-6786-72e1-8405-fe0d66a9aa61" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeLossFromEquityMethodInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019d0150-6786-747a-b17f-55e061ea8b84" xlink:to="loc_us-gaap_IncomeLossFromEquityMethodInvestments_019d0150-6786-72e1-8405-fe0d66a9aa61" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProfitLoss_019d0150-6786-705a-9fac-bd33c1f9348e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ProfitLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019d0150-6786-747a-b17f-55e061ea8b84" xlink:to="loc_us-gaap_ProfitLoss_019d0150-6786-705a-9fac-bd33c1f9348e" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossAttributableToNoncontrollingInterest_019d0150-6786-70cf-9ad6-3eb28c4fddd0" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NetIncomeLossAttributableToNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019d0150-6786-747a-b17f-55e061ea8b84" xlink:to="loc_us-gaap_NetIncomeLossAttributableToNoncontrollingInterest_019d0150-6786-70cf-9ad6-3eb28c4fddd0" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic_019d0150-6786-7543-95d8-401046a999f9" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019d0150-6786-747a-b17f-55e061ea8b84" xlink:to="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic_019d0150-6786-7543-95d8-401046a999f9" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareBasic_019d0150-6786-74fa-a17c-d02132fdc30a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EarningsPerShareBasic"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019d0150-6786-747a-b17f-55e061ea8b84" xlink:to="loc_us-gaap_EarningsPerShareBasic_019d0150-6786-74fa-a17c-d02132fdc30a" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareDiluted_019d0150-6786-7785-8103-2ae49323c5d0" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EarningsPerShareDiluted"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019d0150-6786-747a-b17f-55e061ea8b84" xlink:to="loc_us-gaap_EarningsPerShareDiluted_019d0150-6786-7785-8103-2ae49323c5d0" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingAbstract_019d0150-6786-7369-9965-1d0331fd9f0f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_WeightedAverageNumberOfSharesOutstandingAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019d0150-6786-747a-b17f-55e061ea8b84" xlink:to="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingAbstract_019d0150-6786-7369-9965-1d0331fd9f0f" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_019d0150-6786-7476-83ec-a46cb2f904b0" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_WeightedAverageNumberOfSharesOutstandingBasic"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingAbstract_019d0150-6786-7369-9965-1d0331fd9f0f" xlink:to="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_019d0150-6786-7476-83ec-a46cb2f904b0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_019d0150-6786-771f-bca4-bc29cc31c791" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingAbstract_019d0150-6786-7369-9965-1d0331fd9f0f" xlink:to="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_019d0150-6786-771f-bca4-bc29cc31c791" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.cat.com/role/ConsolidatedStatementofFinancialPosition" xlink:type="simple" xlink:href="cat-20260331.xsd#ConsolidatedStatementofFinancialPosition"/>
  <link:definitionLink xlink:role="http://www.cat.com/role/ConsolidatedStatementofFinancialPosition" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_019d0150-6786-723b-8ce7-19773df160c2" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_019d0150-6786-743c-b17a-d54d39f208a1" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_019d0150-6786-723b-8ce7-19773df160c2" xlink:to="loc_us-gaap_StatementTable_019d0150-6786-743c-b17a-d54d39f208a1" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_019d0150-6786-7997-b6f3-e005df6dd641" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_ProductOrServiceAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_019d0150-6786-743c-b17a-d54d39f208a1" xlink:to="loc_srt_ProductOrServiceAxis_019d0150-6786-7997-b6f3-e005df6dd641" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_019d0150-6786-7997-b6f3-e005df6dd641_default" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_019d0150-6786-7997-b6f3-e005df6dd641" xlink:to="loc_srt_ProductsAndServicesDomain_019d0150-6786-7997-b6f3-e005df6dd641_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_019d0150-6786-7b62-a2f2-c749ee2116ff" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_019d0150-6786-7997-b6f3-e005df6dd641" xlink:to="loc_srt_ProductsAndServicesDomain_019d0150-6786-7b62-a2f2-c749ee2116ff" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_FinancialProductsMember_019d0150-6786-7181-8a56-54e393084a81" xlink:href="cat-20260331.xsd#cat_FinancialProductsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_019d0150-6786-7b62-a2f2-c749ee2116ff" xlink:to="loc_cat_FinancialProductsMember_019d0150-6786-7181-8a56-54e393084a81" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_MachineryPowerEnergyMember_019d0150-6786-753c-ac0e-8281b0729fed" xlink:href="cat-20260331.xsd#cat_MachineryPowerEnergyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_019d0150-6786-7b62-a2f2-c749ee2116ff" xlink:to="loc_cat_MachineryPowerEnergyMember_019d0150-6786-753c-ac0e-8281b0729fed" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsAbstract_019d0150-6786-73b3-88a1-9b5457a4834e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AssetsAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019d0150-6786-723b-8ce7-19773df160c2" xlink:to="loc_us-gaap_AssetsAbstract_019d0150-6786-73b3-88a1-9b5457a4834e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsCurrentAbstract_019d0150-6786-7bcc-8209-5481bc96b04e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AssetsCurrentAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_019d0150-6786-73b3-88a1-9b5457a4834e" xlink:to="loc_us-gaap_AssetsCurrentAbstract_019d0150-6786-7bcc-8209-5481bc96b04e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_019d0150-6786-7118-809e-fc08cb144044" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_019d0150-6786-7bcc-8209-5481bc96b04e" xlink:to="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_019d0150-6786-7118-809e-fc08cb144044" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsReceivableNetCurrent_019d0150-6786-7f93-a9fd-6cfdb7616306" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccountsReceivableNetCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_019d0150-6786-7bcc-8209-5481bc96b04e" xlink:to="loc_us-gaap_AccountsReceivableNetCurrent_019d0150-6786-7f93-a9fd-6cfdb7616306" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NotesAndLoansReceivableNetCurrent_019d0150-6786-7dff-b6d3-9adb36f16730" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NotesAndLoansReceivableNetCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_019d0150-6786-7bcc-8209-5481bc96b04e" xlink:to="loc_us-gaap_NotesAndLoansReceivableNetCurrent_019d0150-6786-7dff-b6d3-9adb36f16730" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PrepaidExpenseAndOtherAssetsCurrent_019d0150-6786-7c13-a538-6c2ca1e11e56" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PrepaidExpenseAndOtherAssetsCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_019d0150-6786-7bcc-8209-5481bc96b04e" xlink:to="loc_us-gaap_PrepaidExpenseAndOtherAssetsCurrent_019d0150-6786-7c13-a538-6c2ca1e11e56" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InventoryNet_019d0150-6786-7566-b951-7323d5ec24f3" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_InventoryNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_019d0150-6786-7bcc-8209-5481bc96b04e" xlink:to="loc_us-gaap_InventoryNet_019d0150-6786-7566-b951-7323d5ec24f3" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsCurrent_019d0150-6786-7e39-96b1-2bb07599b89c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AssetsCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_019d0150-6786-7bcc-8209-5481bc96b04e" xlink:to="loc_us-gaap_AssetsCurrent_019d0150-6786-7e39-96b1-2bb07599b89c" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentNet_019d0150-6786-7180-9f10-96056f010bf8" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PropertyPlantAndEquipmentNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_019d0150-6786-73b3-88a1-9b5457a4834e" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentNet_019d0150-6786-7180-9f10-96056f010bf8" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsReceivableNetNoncurrent_019d0150-6786-76ee-b84f-1ac75f530851" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccountsReceivableNetNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_019d0150-6786-73b3-88a1-9b5457a4834e" xlink:to="loc_us-gaap_AccountsReceivableNetNoncurrent_019d0150-6786-76ee-b84f-1ac75f530851" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NotesAndLoansReceivableNetNoncurrent_019d0150-6786-724e-99c4-b03194496546" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NotesAndLoansReceivableNetNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_019d0150-6786-73b3-88a1-9b5457a4834e" xlink:to="loc_us-gaap_NotesAndLoansReceivableNetNoncurrent_019d0150-6786-724e-99c4-b03194496546" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_NoncurrentDeferredAndRefundableIncomeTaxes_019d0150-6786-7689-8b0e-dc949e03b894" xlink:href="cat-20260331.xsd#cat_NoncurrentDeferredAndRefundableIncomeTaxes"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_019d0150-6786-73b3-88a1-9b5457a4834e" xlink:to="loc_cat_NoncurrentDeferredAndRefundableIncomeTaxes_019d0150-6786-7689-8b0e-dc949e03b894" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IntangibleAssetsNetExcludingGoodwill_019d0150-6786-771d-94a3-a264ae07de0e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IntangibleAssetsNetExcludingGoodwill"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_019d0150-6786-73b3-88a1-9b5457a4834e" xlink:to="loc_us-gaap_IntangibleAssetsNetExcludingGoodwill_019d0150-6786-771d-94a3-a264ae07de0e" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Goodwill_019d0150-6786-7256-9758-007cb6bf5b5c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_Goodwill"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_019d0150-6786-73b3-88a1-9b5457a4834e" xlink:to="loc_us-gaap_Goodwill_019d0150-6786-7256-9758-007cb6bf5b5c" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherAssetsNoncurrent_019d0150-6786-7b7e-ab63-06a1fcb7e37d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherAssetsNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_019d0150-6786-73b3-88a1-9b5457a4834e" xlink:to="loc_us-gaap_OtherAssetsNoncurrent_019d0150-6786-7b7e-ab63-06a1fcb7e37d" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Assets_019d0150-6786-70ac-8b4b-1f002729ec32" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_Assets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_019d0150-6786-73b3-88a1-9b5457a4834e" xlink:to="loc_us-gaap_Assets_019d0150-6786-70ac-8b4b-1f002729ec32" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesAbstract_019d0150-6786-745f-aa2b-00d8449546c0" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LiabilitiesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019d0150-6786-723b-8ce7-19773df160c2" xlink:to="loc_us-gaap_LiabilitiesAbstract_019d0150-6786-745f-aa2b-00d8449546c0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesCurrentAbstract_019d0150-6786-7395-b6e9-a17d7981ecd9" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LiabilitiesCurrentAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAbstract_019d0150-6786-745f-aa2b-00d8449546c0" xlink:to="loc_us-gaap_LiabilitiesCurrentAbstract_019d0150-6786-7395-b6e9-a17d7981ecd9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermBorrowingsAbstract_019d0150-6786-7e00-9b45-c79d32f442a7" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShortTermBorrowingsAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_019d0150-6786-7395-b6e9-a17d7981ecd9" xlink:to="loc_us-gaap_ShortTermBorrowingsAbstract_019d0150-6786-7e00-9b45-c79d32f442a7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermBorrowings_019d0150-6786-7a5d-9746-bff5e2529e81" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShortTermBorrowings"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortTermBorrowingsAbstract_019d0150-6786-7e00-9b45-c79d32f442a7" xlink:to="loc_us-gaap_ShortTermBorrowings_019d0150-6786-7a5d-9746-bff5e2529e81" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsPayableCurrent_019d0150-6786-7647-8535-c34f7711fa3b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccountsPayableCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_019d0150-6786-7395-b6e9-a17d7981ecd9" xlink:to="loc_us-gaap_AccountsPayableCurrent_019d0150-6786-7647-8535-c34f7711fa3b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccruedLiabilitiesCurrent_019d0150-6786-7818-98ec-5d9db76f1d4d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccruedLiabilitiesCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_019d0150-6786-7395-b6e9-a17d7981ecd9" xlink:to="loc_us-gaap_AccruedLiabilitiesCurrent_019d0150-6786-7818-98ec-5d9db76f1d4d" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeRelatedLiabilitiesCurrent_019d0150-6786-76de-b21d-c9362d3df515" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EmployeeRelatedLiabilitiesCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_019d0150-6786-7395-b6e9-a17d7981ecd9" xlink:to="loc_us-gaap_EmployeeRelatedLiabilitiesCurrent_019d0150-6786-76de-b21d-c9362d3df515" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerLiabilityCurrent_019d0150-6786-70d7-b71c-0f5155fe8c6a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ContractWithCustomerLiabilityCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_019d0150-6786-7395-b6e9-a17d7981ecd9" xlink:to="loc_us-gaap_ContractWithCustomerLiabilityCurrent_019d0150-6786-70d7-b71c-0f5155fe8c6a" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DividendsPayableCurrent_019d0150-6786-7610-8a0b-3da39e73f631" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DividendsPayableCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_019d0150-6786-7395-b6e9-a17d7981ecd9" xlink:to="loc_us-gaap_DividendsPayableCurrent_019d0150-6786-7610-8a0b-3da39e73f631" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherLiabilitiesCurrent_019d0150-6786-7b7a-bb4d-c7495a64e95f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherLiabilitiesCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_019d0150-6786-7395-b6e9-a17d7981ecd9" xlink:to="loc_us-gaap_OtherLiabilitiesCurrent_019d0150-6786-7b7a-bb4d-c7495a64e95f" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtCurrentAbstract_019d0150-6786-7bd5-a4a2-dc967c74e67a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LongTermDebtCurrentAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_019d0150-6786-7395-b6e9-a17d7981ecd9" xlink:to="loc_us-gaap_LongTermDebtCurrentAbstract_019d0150-6786-7bd5-a4a2-dc967c74e67a" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtAndCapitalLeaseObligationsCurrent_019d0150-6786-7bb3-8a62-cc593645479f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LongTermDebtAndCapitalLeaseObligationsCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongTermDebtCurrentAbstract_019d0150-6786-7bd5-a4a2-dc967c74e67a" xlink:to="loc_us-gaap_LongTermDebtAndCapitalLeaseObligationsCurrent_019d0150-6786-7bb3-8a62-cc593645479f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesCurrent_019d0150-6786-7af4-a225-b853fcd71998" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LiabilitiesCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_019d0150-6786-7395-b6e9-a17d7981ecd9" xlink:to="loc_us-gaap_LiabilitiesCurrent_019d0150-6786-7af4-a225-b853fcd71998" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtNoncurrentAbstract_019d0150-6786-7079-b331-7566760250ef" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LongTermDebtNoncurrentAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAbstract_019d0150-6786-745f-aa2b-00d8449546c0" xlink:to="loc_us-gaap_LongTermDebtNoncurrentAbstract_019d0150-6786-7079-b331-7566760250ef" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtAndCapitalLeaseObligations_019d0150-6786-74cb-89e2-d06429e51cb5" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LongTermDebtAndCapitalLeaseObligations"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongTermDebtNoncurrentAbstract_019d0150-6786-7079-b331-7566760250ef" xlink:to="loc_us-gaap_LongTermDebtAndCapitalLeaseObligations_019d0150-6786-74cb-89e2-d06429e51cb5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PensionAndOtherPostretirementAndPostemploymentBenefitPlansLiabilitiesNoncurrent_019d0150-6786-7c63-ab17-b9590608dece" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PensionAndOtherPostretirementAndPostemploymentBenefitPlansLiabilitiesNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAbstract_019d0150-6786-745f-aa2b-00d8449546c0" xlink:to="loc_us-gaap_PensionAndOtherPostretirementAndPostemploymentBenefitPlansLiabilitiesNoncurrent_019d0150-6786-7c63-ab17-b9590608dece" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherLiabilitiesNoncurrent_019d0150-6786-7967-9826-de38dd418d2c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherLiabilitiesNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAbstract_019d0150-6786-745f-aa2b-00d8449546c0" xlink:to="loc_us-gaap_OtherLiabilitiesNoncurrent_019d0150-6786-7967-9826-de38dd418d2c" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Liabilities_019d0150-6786-79f5-b41f-ba05e0caa0bc" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_Liabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAbstract_019d0150-6786-745f-aa2b-00d8449546c0" xlink:to="loc_us-gaap_Liabilities_019d0150-6786-79f5-b41f-ba05e0caa0bc" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommitmentsAndContingencies_019d0150-6786-7555-8609-f99e1838307c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CommitmentsAndContingencies"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019d0150-6786-723b-8ce7-19773df160c2" xlink:to="loc_us-gaap_CommitmentsAndContingencies_019d0150-6786-7555-8609-f99e1838307c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAbstract_019d0150-6786-7913-b32c-03a5372124b7" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019d0150-6786-723b-8ce7-19773df160c2" xlink:to="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAbstract_019d0150-6786-7913-b32c-03a5372124b7" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStocksIncludingAdditionalPaidInCapital_019d0150-6786-7384-81be-049381c07b08" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CommonStocksIncludingAdditionalPaidInCapital"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAbstract_019d0150-6786-7913-b32c-03a5372124b7" xlink:to="loc_us-gaap_CommonStocksIncludingAdditionalPaidInCapital_019d0150-6786-7384-81be-049381c07b08" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TreasuryStockValue_019d0150-6786-7258-980d-ff5b9d6548e3" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_TreasuryStockValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAbstract_019d0150-6786-7913-b32c-03a5372124b7" xlink:to="loc_us-gaap_TreasuryStockValue_019d0150-6786-7258-980d-ff5b9d6548e3" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetainedEarningsAccumulatedDeficit_019d0150-6786-75ca-8bd0-d1927b4ce843" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RetainedEarningsAccumulatedDeficit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAbstract_019d0150-6786-7913-b32c-03a5372124b7" xlink:to="loc_us-gaap_RetainedEarningsAccumulatedDeficit_019d0150-6786-75ca-8bd0-d1927b4ce843" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_019d0150-6786-775c-812a-d4019469a607" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAbstract_019d0150-6786-7913-b32c-03a5372124b7" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_019d0150-6786-775c-812a-d4019469a607" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MinorityInterest_019d0150-6786-7b60-b6e8-5ecd2afc0feb" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_MinorityInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAbstract_019d0150-6786-7913-b32c-03a5372124b7" xlink:to="loc_us-gaap_MinorityInterest_019d0150-6786-7b60-b6e8-5ecd2afc0feb" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_019d0150-6786-7129-87ff-371f5123accc" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAbstract_019d0150-6786-7913-b32c-03a5372124b7" xlink:to="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_019d0150-6786-7129-87ff-371f5123accc" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquity_019d0150-6786-7960-a783-f93bce96e162" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LiabilitiesAndStockholdersEquity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019d0150-6786-723b-8ce7-19773df160c2" xlink:to="loc_us-gaap_LiabilitiesAndStockholdersEquity_019d0150-6786-7960-a783-f93bce96e162" xlink:type="arc" order="4"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.cat.com/role/ConsolidatedStatementofChangesinShareholdersEquity" xlink:type="simple" xlink:href="cat-20260331.xsd#ConsolidatedStatementofChangesinShareholdersEquity"/>
  <link:definitionLink xlink:role="http://www.cat.com/role/ConsolidatedStatementofChangesinShareholdersEquity" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_019d0150-6786-7323-b83c-f3efa29c66fa" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_019d0150-6786-786a-9b3b-fd9d34839372" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_019d0150-6786-7323-b83c-f3efa29c66fa" xlink:to="loc_us-gaap_StatementTable_019d0150-6786-786a-9b3b-fd9d34839372" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_019d0150-6786-7601-b2ed-2dca76ba210e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_019d0150-6786-786a-9b3b-fd9d34839372" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_019d0150-6786-7601-b2ed-2dca76ba210e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_019d0150-6786-7601-b2ed-2dca76ba210e_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_019d0150-6786-7601-b2ed-2dca76ba210e" xlink:to="loc_us-gaap_EquityComponentDomain_019d0150-6786-7601-b2ed-2dca76ba210e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_019d0150-6786-717e-b7fe-5e55aea6c61f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_019d0150-6786-7601-b2ed-2dca76ba210e" xlink:to="loc_us-gaap_EquityComponentDomain_019d0150-6786-717e-b7fe-5e55aea6c61f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockIncludingAdditionalPaidInCapitalMember_019d0150-6786-755c-8d52-3ef72f0d5b4c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CommonStockIncludingAdditionalPaidInCapitalMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_019d0150-6786-717e-b7fe-5e55aea6c61f" xlink:to="loc_us-gaap_CommonStockIncludingAdditionalPaidInCapitalMember_019d0150-6786-755c-8d52-3ef72f0d5b4c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TreasuryStockCommonMember_019d0150-6786-7fa8-8b8f-db290281f35e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_TreasuryStockCommonMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_019d0150-6786-717e-b7fe-5e55aea6c61f" xlink:to="loc_us-gaap_TreasuryStockCommonMember_019d0150-6786-7fa8-8b8f-db290281f35e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetainedEarningsMember_019d0150-6786-7a56-b683-874ba5ce4d50" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RetainedEarningsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_019d0150-6786-717e-b7fe-5e55aea6c61f" xlink:to="loc_us-gaap_RetainedEarningsMember_019d0150-6786-7a56-b683-874ba5ce4d50" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_019d0150-6786-799b-953a-f8ce61c9ec3a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_019d0150-6786-717e-b7fe-5e55aea6c61f" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_019d0150-6786-799b-953a-f8ce61c9ec3a" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NoncontrollingInterestMember_019d0150-6786-7300-9d29-f74b73714f06" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NoncontrollingInterestMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_019d0150-6786-717e-b7fe-5e55aea6c61f" xlink:to="loc_us-gaap_NoncontrollingInterestMember_019d0150-6786-7300-9d29-f74b73714f06" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019d0150-6786-7eff-b180-a0b47a52edec" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncreaseDecreaseInStockholdersEquityRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019d0150-6786-7323-b83c-f3efa29c66fa" xlink:to="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019d0150-6786-7eff-b180-a0b47a52edec" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_019d0150-6786-7f01-a387-9385cb4de1ae" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019d0150-6786-7eff-b180-a0b47a52edec" xlink:to="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_019d0150-6786-7f01-a387-9385cb4de1ae" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProfitLoss_019d0150-6786-7829-9c32-2901fa1bd9e9" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ProfitLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019d0150-6786-7eff-b180-a0b47a52edec" xlink:to="loc_us-gaap_ProfitLoss_019d0150-6786-7829-9c32-2901fa1bd9e9" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax_019d0150-6786-7891-98c5-ef6cf2675539" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019d0150-6786-7eff-b180-a0b47a52edec" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax_019d0150-6786-7891-98c5-ef6cf2675539" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax_019d0150-6786-75d8-9178-0d4c94c7456c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019d0150-6786-7eff-b180-a0b47a52edec" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax_019d0150-6786-75d8-9178-0d4c94c7456c" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationAndTaxParent_019d0150-6786-7766-98e5-407bcc4c503b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationAndTaxParent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019d0150-6786-7eff-b180-a0b47a52edec" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationAndTaxParent_019d0150-6786-7766-98e5-407bcc4c503b" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax_019d0150-6786-70ba-8e56-a7e2b09abc94" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019d0150-6786-7eff-b180-a0b47a52edec" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax_019d0150-6786-70ba-8e56-a7e2b09abc94" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_DividendsCommonStockCashNet_019d0150-6786-7cc4-ad09-e4e0b89da47b" xlink:href="cat-20260331.xsd#cat_DividendsCommonStockCashNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019d0150-6786-7eff-b180-a0b47a52edec" xlink:to="loc_cat_DividendsCommonStockCashNet_019d0150-6786-7cc4-ad09-e4e0b89da47b" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_ValueOfCommonSharesIssuedFromTreasuryStockForStockBasedCompensation_019d0150-6786-7891-a4f3-ffff4fb41a81" xlink:href="cat-20260331.xsd#cat_ValueOfCommonSharesIssuedFromTreasuryStockForStockBasedCompensation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019d0150-6786-7eff-b180-a0b47a52edec" xlink:to="loc_cat_ValueOfCommonSharesIssuedFromTreasuryStockForStockBasedCompensation_019d0150-6786-7891-a4f3-ffff4fb41a81" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_019d0150-6786-71e8-b3a8-5e6fb4819733" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019d0150-6786-7eff-b180-a0b47a52edec" xlink:to="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_019d0150-6786-71e8-b3a8-5e6fb4819733" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TreasuryStockValueAcquiredCostMethod_019d0150-6786-76ba-b305-fba80b226c8b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_TreasuryStockValueAcquiredCostMethod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019d0150-6786-7eff-b180-a0b47a52edec" xlink:to="loc_us-gaap_TreasuryStockValueAcquiredCostMethod_019d0150-6786-76ba-b305-fba80b226c8b" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AcceleratedShareRepurchaseProgramAdjustment_019d0150-6786-78d8-bdb5-73c3e032991e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AcceleratedShareRepurchaseProgramAdjustment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019d0150-6786-7eff-b180-a0b47a52edec" xlink:to="loc_us-gaap_AcceleratedShareRepurchaseProgramAdjustment_019d0150-6786-78d8-bdb5-73c3e032991e" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityOther_019d0150-6786-79a5-abf8-20534ce5d5c6" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StockholdersEquityOther"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019d0150-6786-7eff-b180-a0b47a52edec" xlink:to="loc_us-gaap_StockholdersEquityOther_019d0150-6786-79a5-abf8-20534ce5d5c6" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_019d0150-6786-79ed-bb48-5fc0b215af86" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.cat.com/role/ConsolidatedStatementofCashFlow" xlink:type="simple" xlink:href="cat-20260331.xsd#ConsolidatedStatementofCashFlow"/>
  <link:definitionLink xlink:role="http://www.cat.com/role/ConsolidatedStatementofCashFlow" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_019d0150-6786-7537-a0ae-f56456d7b9c7" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_019d0150-6786-7842-b33d-ea3c6a74d7a5" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_019d0150-6786-7537-a0ae-f56456d7b9c7" xlink:to="loc_us-gaap_StatementTable_019d0150-6786-7842-b33d-ea3c6a74d7a5" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_019d0150-6786-7b83-98d9-88aa2663216a" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_ProductOrServiceAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_019d0150-6786-7842-b33d-ea3c6a74d7a5" xlink:to="loc_srt_ProductOrServiceAxis_019d0150-6786-7b83-98d9-88aa2663216a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_019d0150-6786-7b83-98d9-88aa2663216a_default" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_019d0150-6786-7b83-98d9-88aa2663216a" xlink:to="loc_srt_ProductsAndServicesDomain_019d0150-6786-7b83-98d9-88aa2663216a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_019d0150-6786-738d-b7a9-e2bcc220c773" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_019d0150-6786-7b83-98d9-88aa2663216a" xlink:to="loc_srt_ProductsAndServicesDomain_019d0150-6786-738d-b7a9-e2bcc220c773" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_MachineryPowerEnergyMember_019d0150-6786-7604-80aa-94d5f96cb340" xlink:href="cat-20260331.xsd#cat_MachineryPowerEnergyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_019d0150-6786-738d-b7a9-e2bcc220c773" xlink:to="loc_cat_MachineryPowerEnergyMember_019d0150-6786-7604-80aa-94d5f96cb340" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_FinancialProductsMember_019d0150-6786-77b1-9cb3-7f93886439a8" xlink:href="cat-20260331.xsd#cat_FinancialProductsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_019d0150-6786-738d-b7a9-e2bcc220c773" xlink:to="loc_cat_FinancialProductsMember_019d0150-6786-77b1-9cb3-7f93886439a8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperationsAbstract_019d0150-6786-7b9f-a621-fe2305a85f8b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperationsAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019d0150-6786-7537-a0ae-f56456d7b9c7" xlink:to="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperationsAbstract_019d0150-6786-7b9f-a621-fe2305a85f8b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProfitLoss_019d0150-6786-7525-9502-2ef6d6f244a8" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ProfitLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperationsAbstract_019d0150-6786-7b9f-a621-fe2305a85f8b" xlink:to="loc_us-gaap_ProfitLoss_019d0150-6786-7525-9502-2ef6d6f244a8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsNoncashItemsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_019d0150-6786-7cd8-bd8b-12560f57adc3" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AdjustmentsNoncashItemsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperationsAbstract_019d0150-6786-7b9f-a621-fe2305a85f8b" xlink:to="loc_us-gaap_AdjustmentsNoncashItemsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_019d0150-6786-7cd8-bd8b-12560f57adc3" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DepreciationDepletionAndAmortization_019d0150-6786-747c-b85b-f5a5e81710a9" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DepreciationDepletionAndAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsNoncashItemsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_019d0150-6786-7cd8-bd8b-12560f57adc3" xlink:to="loc_us-gaap_DepreciationDepletionAndAmortization_019d0150-6786-747c-b85b-f5a5e81710a9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredIncomeTaxExpenseBenefit_019d0150-6786-78d1-861c-4535c0b11c3e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DeferredIncomeTaxExpenseBenefit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsNoncashItemsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_019d0150-6786-7cd8-bd8b-12560f57adc3" xlink:to="loc_us-gaap_DeferredIncomeTaxExpenseBenefit_019d0150-6786-78d1-861c-4535c0b11c3e" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherNoncashIncomeExpense_019d0150-6786-737d-87b4-f6330b8ae6c2" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherNoncashIncomeExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsNoncashItemsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_019d0150-6786-7cd8-bd8b-12560f57adc3" xlink:to="loc_us-gaap_OtherNoncashIncomeExpense_019d0150-6786-737d-87b4-f6330b8ae6c2" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_019d0150-6786-7ea0-9c24-e7f9484a8bb9" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncreaseDecreaseInOperatingCapitalAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperationsAbstract_019d0150-6786-7b9f-a621-fe2305a85f8b" xlink:to="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_019d0150-6786-7ea0-9c24-e7f9484a8bb9" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInReceivables_019d0150-6786-7b27-a76b-c195c0d6ba3b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncreaseDecreaseInReceivables"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_019d0150-6786-7ea0-9c24-e7f9484a8bb9" xlink:to="loc_us-gaap_IncreaseDecreaseInReceivables_019d0150-6786-7b27-a76b-c195c0d6ba3b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInInventories_019d0150-6786-78eb-a141-253cf228d1a7" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncreaseDecreaseInInventories"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_019d0150-6786-7ea0-9c24-e7f9484a8bb9" xlink:to="loc_us-gaap_IncreaseDecreaseInInventories_019d0150-6786-78eb-a141-253cf228d1a7" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInAccountsPayable_019d0150-6786-703e-8b35-48aa4d43bd44" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncreaseDecreaseInAccountsPayable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_019d0150-6786-7ea0-9c24-e7f9484a8bb9" xlink:to="loc_us-gaap_IncreaseDecreaseInAccountsPayable_019d0150-6786-703e-8b35-48aa4d43bd44" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInAccruedLiabilities_019d0150-6786-7bbf-8f5f-c824deae24c0" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncreaseDecreaseInAccruedLiabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_019d0150-6786-7ea0-9c24-e7f9484a8bb9" xlink:to="loc_us-gaap_IncreaseDecreaseInAccruedLiabilities_019d0150-6786-7bbf-8f5f-c824deae24c0" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInEmployeeRelatedLiabilities_019d0150-6786-7ec0-aac9-b58fd5cc2614" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncreaseDecreaseInEmployeeRelatedLiabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_019d0150-6786-7ea0-9c24-e7f9484a8bb9" xlink:to="loc_us-gaap_IncreaseDecreaseInEmployeeRelatedLiabilities_019d0150-6786-7ec0-aac9-b58fd5cc2614" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInContractWithCustomerLiability_019d0150-6786-7626-98a9-80c1bdab5b12" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncreaseDecreaseInContractWithCustomerLiability"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_019d0150-6786-7ea0-9c24-e7f9484a8bb9" xlink:to="loc_us-gaap_IncreaseDecreaseInContractWithCustomerLiability_019d0150-6786-7626-98a9-80c1bdab5b12" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInOtherOperatingAssets_019d0150-6786-7253-8fba-344992674173" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncreaseDecreaseInOtherOperatingAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_019d0150-6786-7ea0-9c24-e7f9484a8bb9" xlink:to="loc_us-gaap_IncreaseDecreaseInOtherOperatingAssets_019d0150-6786-7253-8fba-344992674173" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInOtherOperatingLiabilities_019d0150-6786-7a7b-bf4a-0e18149cc18f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncreaseDecreaseInOtherOperatingLiabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_019d0150-6786-7ea0-9c24-e7f9484a8bb9" xlink:to="loc_us-gaap_IncreaseDecreaseInOtherOperatingLiabilities_019d0150-6786-7a7b-bf4a-0e18149cc18f" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_019d0150-6786-74cf-bea5-7b0e8bf43cdd" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperationsAbstract_019d0150-6786-7b9f-a621-fe2305a85f8b" xlink:to="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_019d0150-6786-74cf-bea5-7b0e8bf43cdd" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperationsAbstract_019d0150-6786-7564-9397-5f4e890656df" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperationsAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019d0150-6786-7537-a0ae-f56456d7b9c7" xlink:to="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperationsAbstract_019d0150-6786-7564-9397-5f4e890656df" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_019d0150-6786-7aae-b06a-9cf46ac268b9" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PaymentsToAcquirePropertyPlantAndEquipment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperationsAbstract_019d0150-6786-7564-9397-5f4e890656df" xlink:to="loc_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_019d0150-6786-7aae-b06a-9cf46ac268b9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsToAcquireEquipmentOnLease_019d0150-6786-7963-a8be-4396a8c9a4fc" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PaymentsToAcquireEquipmentOnLease"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperationsAbstract_019d0150-6786-7564-9397-5f4e890656df" xlink:to="loc_us-gaap_PaymentsToAcquireEquipmentOnLease_019d0150-6786-7963-a8be-4396a8c9a4fc" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromSaleOfPropertyPlantAndEquipment_019d0150-6786-723d-a654-e96659604283" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ProceedsFromSaleOfPropertyPlantAndEquipment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperationsAbstract_019d0150-6786-7564-9397-5f4e890656df" xlink:to="loc_us-gaap_ProceedsFromSaleOfPropertyPlantAndEquipment_019d0150-6786-723d-a654-e96659604283" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsToAcquireFinanceReceivables_019d0150-6786-7f20-87e1-5e31c1107dbd" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PaymentsToAcquireFinanceReceivables"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperationsAbstract_019d0150-6786-7564-9397-5f4e890656df" xlink:to="loc_us-gaap_PaymentsToAcquireFinanceReceivables_019d0150-6786-7f20-87e1-5e31c1107dbd" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromCollectionOfFinanceReceivables_019d0150-6786-79eb-a4e6-6e1188cff922" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ProceedsFromCollectionOfFinanceReceivables"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperationsAbstract_019d0150-6786-7564-9397-5f4e890656df" xlink:to="loc_us-gaap_ProceedsFromCollectionOfFinanceReceivables_019d0150-6786-79eb-a4e6-6e1188cff922" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromSaleOfFinanceReceivables_019d0150-6786-7c01-8eb0-a205c5489c50" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ProceedsFromSaleOfFinanceReceivables"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperationsAbstract_019d0150-6786-7564-9397-5f4e890656df" xlink:to="loc_us-gaap_ProceedsFromSaleOfFinanceReceivables_019d0150-6786-7c01-8eb0-a205c5489c50" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired_019d0150-6786-73bd-b1ce-7c935a738eaf" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperationsAbstract_019d0150-6786-7564-9397-5f4e890656df" xlink:to="loc_us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired_019d0150-6786-73bd-b1ce-7c935a738eaf" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromDivestitureOfBusinessesNetOfCashDivested_019d0150-6786-7e4c-8761-e7aa65c0cdf6" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ProceedsFromDivestitureOfBusinessesNetOfCashDivested"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperationsAbstract_019d0150-6786-7564-9397-5f4e890656df" xlink:to="loc_us-gaap_ProceedsFromDivestitureOfBusinessesNetOfCashDivested_019d0150-6786-7e4c-8761-e7aa65c0cdf6" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromSaleAndMaturityOfMarketableSecurities_019d0150-6786-77c2-8de0-616fd2c936af" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ProceedsFromSaleAndMaturityOfMarketableSecurities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperationsAbstract_019d0150-6786-7564-9397-5f4e890656df" xlink:to="loc_us-gaap_ProceedsFromSaleAndMaturityOfMarketableSecurities_019d0150-6786-77c2-8de0-616fd2c936af" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsToAcquireMarketableSecurities_019d0150-6786-773d-afee-01dc2d11d75e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PaymentsToAcquireMarketableSecurities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperationsAbstract_019d0150-6786-7564-9397-5f4e890656df" xlink:to="loc_us-gaap_PaymentsToAcquireMarketableSecurities_019d0150-6786-773d-afee-01dc2d11d75e" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsForProceedsFromOtherInvestingActivities_019d0150-6786-79d4-a888-7f0ab9a10e3f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PaymentsForProceedsFromOtherInvestingActivities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperationsAbstract_019d0150-6786-7564-9397-5f4e890656df" xlink:to="loc_us-gaap_PaymentsForProceedsFromOtherInvestingActivities_019d0150-6786-79d4-a888-7f0ab9a10e3f" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_019d0150-6786-7ad5-93d9-4b92e28d7eb4" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperationsAbstract_019d0150-6786-7564-9397-5f4e890656df" xlink:to="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_019d0150-6786-7ad5-93d9-4b92e28d7eb4" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperationsAbstract_019d0150-6786-7aef-a796-38d0a0657db1" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperationsAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019d0150-6786-7537-a0ae-f56456d7b9c7" xlink:to="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperationsAbstract_019d0150-6786-7aef-a796-38d0a0657db1" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsOfDividendsCommonStock_019d0150-6786-7723-afc4-8a642c8d7240" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PaymentsOfDividendsCommonStock"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperationsAbstract_019d0150-6786-7aef-a796-38d0a0657db1" xlink:to="loc_us-gaap_PaymentsOfDividendsCommonStock_019d0150-6786-7723-afc4-8a642c8d7240" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromIssuanceOrSaleOfEquity_019d0150-6786-7e49-9451-ac0630dd362c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ProceedsFromIssuanceOrSaleOfEquity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperationsAbstract_019d0150-6786-7aef-a796-38d0a0657db1" xlink:to="loc_us-gaap_ProceedsFromIssuanceOrSaleOfEquity_019d0150-6786-7e49-9451-ac0630dd362c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsForRepurchaseOfCommonStock_019d0150-6786-7ef0-98e1-65810a113ba3" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PaymentsForRepurchaseOfCommonStock"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperationsAbstract_019d0150-6786-7aef-a796-38d0a0657db1" xlink:to="loc_us-gaap_PaymentsForRepurchaseOfCommonStock_019d0150-6786-7ef0-98e1-65810a113ba3" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromDebtMaturingInMoreThanThreeMonths_019d0150-6786-7147-9d87-33898fde5528" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ProceedsFromDebtMaturingInMoreThanThreeMonths"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperationsAbstract_019d0150-6786-7aef-a796-38d0a0657db1" xlink:to="loc_us-gaap_ProceedsFromDebtMaturingInMoreThanThreeMonths_019d0150-6786-7147-9d87-33898fde5528" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RepaymentsOfDebtMaturingInMoreThanThreeMonths_019d0150-6786-767d-9877-b25a8dce5d1f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RepaymentsOfDebtMaturingInMoreThanThreeMonths"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperationsAbstract_019d0150-6786-7aef-a796-38d0a0657db1" xlink:to="loc_us-gaap_RepaymentsOfDebtMaturingInMoreThanThreeMonths_019d0150-6786-767d-9877-b25a8dce5d1f" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromRepaymentsOfShortTermDebtMaturingInThreeMonthsOrLess_019d0150-6786-7862-a3d8-93b2ddaf2b73" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ProceedsFromRepaymentsOfShortTermDebtMaturingInThreeMonthsOrLess"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperationsAbstract_019d0150-6786-7aef-a796-38d0a0657db1" xlink:to="loc_us-gaap_ProceedsFromRepaymentsOfShortTermDebtMaturingInThreeMonthsOrLess_019d0150-6786-7862-a3d8-93b2ddaf2b73" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_019d0150-6786-796f-aae4-428ab5c75071" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperationsAbstract_019d0150-6786-7aef-a796-38d0a0657db1" xlink:to="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_019d0150-6786-796f-aae4-428ab5c75071" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_019d0150-6786-7ec3-8327-52892a42d718" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019d0150-6786-7537-a0ae-f56456d7b9c7" xlink:to="loc_us-gaap_EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_019d0150-6786-7ec3-8327-52892a42d718" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect_019d0150-6786-7a58-8aa8-7e9899a11299" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019d0150-6786-7537-a0ae-f56456d7b9c7" xlink:to="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect_019d0150-6786-7a58-8aa8-7e9899a11299" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_019d0150-6786-7a19-9cc7-9335126ab446" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019d0150-6786-7537-a0ae-f56456d7b9c7" xlink:to="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_019d0150-6786-7a19-9cc7-9335126ab446" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_019d0150-6786-7db6-bb65-ddbd76314ef4" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.cat.com/role/NatureofOperationsandBasisofPresentationDetails" xlink:type="simple" xlink:href="cat-20260331.xsd#NatureofOperationsandBasisofPresentationDetails"/>
  <link:definitionLink xlink:role="http://www.cat.com/role/NatureofOperationsandBasisofPresentationDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_cat_OperationsAndSummaryOfSignificantAccountingPoliciesLineItems_019dc042-5ad5-7433-82b5-11137489f1c7" xlink:href="cat-20260331.xsd#cat_OperationsAndSummaryOfSignificantAccountingPoliciesLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_OperationsAndSummaryOfSignificantAccountingPoliciesTable_019dc042-5ad5-7c94-a7d1-cf79d1a900ba" xlink:href="cat-20260331.xsd#cat_OperationsAndSummaryOfSignificantAccountingPoliciesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_cat_OperationsAndSummaryOfSignificantAccountingPoliciesLineItems_019dc042-5ad5-7433-82b5-11137489f1c7" xlink:to="loc_cat_OperationsAndSummaryOfSignificantAccountingPoliciesTable_019dc042-5ad5-7c94-a7d1-cf79d1a900ba" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_FinanceReceivablesAxis_019dc042-5ad5-78e9-a13c-5e7cbec02bf9" xlink:href="cat-20260331.xsd#cat_FinanceReceivablesAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_cat_OperationsAndSummaryOfSignificantAccountingPoliciesTable_019dc042-5ad5-7c94-a7d1-cf79d1a900ba" xlink:to="loc_cat_FinanceReceivablesAxis_019dc042-5ad5-78e9-a13c-5e7cbec02bf9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_FinanceReceivablesDomain_019dc042-5ad5-78e9-a13c-5e7cbec02bf9_default" xlink:href="cat-20260331.xsd#cat_FinanceReceivablesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_cat_FinanceReceivablesAxis_019dc042-5ad5-78e9-a13c-5e7cbec02bf9" xlink:to="loc_cat_FinanceReceivablesDomain_019dc042-5ad5-78e9-a13c-5e7cbec02bf9_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_FinanceReceivablesDomain_019dc042-5ad5-77ff-99cc-df3ec3f2659e" xlink:href="cat-20260331.xsd#cat_FinanceReceivablesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_cat_FinanceReceivablesAxis_019dc042-5ad5-78e9-a13c-5e7cbec02bf9" xlink:to="loc_cat_FinanceReceivablesDomain_019dc042-5ad5-77ff-99cc-df3ec3f2659e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_RecoveriesFromOverPaymentsMember_019dc042-5ad5-7afe-9780-57d05a6dd72b" xlink:href="cat-20260331.xsd#cat_RecoveriesFromOverPaymentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cat_FinanceReceivablesDomain_019dc042-5ad5-77ff-99cc-df3ec3f2659e" xlink:to="loc_cat_RecoveriesFromOverPaymentsMember_019dc042-5ad5-7afe-9780-57d05a6dd72b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsReceivableNetNoncurrent_019dc042-5ad5-73f9-8ff3-5bdd142b2c3c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccountsReceivableNetNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cat_OperationsAndSummaryOfSignificantAccountingPoliciesLineItems_019dc042-5ad5-7433-82b5-11137489f1c7" xlink:to="loc_us-gaap_AccountsReceivableNetNoncurrent_019dc042-5ad5-73f9-8ff3-5bdd142b2c3c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsReceivableNetCurrent_019dc043-2707-76b8-a705-80aeff6149fb" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccountsReceivableNetCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cat_OperationsAndSummaryOfSignificantAccountingPoliciesLineItems_019dc042-5ad5-7433-82b5-11137489f1c7" xlink:to="loc_us-gaap_AccountsReceivableNetCurrent_019dc043-2707-76b8-a705-80aeff6149fb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_CumulativeTariffsPaid_019dbb4e-c7b0-7049-b91d-3a6d692225f0" xlink:href="cat-20260331.xsd#cat_CumulativeTariffsPaid"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cat_OperationsAndSummaryOfSignificantAccountingPoliciesLineItems_019dc042-5ad5-7433-82b5-11137489f1c7" xlink:to="loc_cat_CumulativeTariffsPaid_019dbb4e-c7b0-7049-b91d-3a6d692225f0" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.cat.com/role/SalesandRevenueContractInformationDetails" xlink:type="simple" xlink:href="cat-20260331.xsd#SalesandRevenueContractInformationDetails"/>
  <link:definitionLink xlink:role="http://www.cat.com/role/SalesandRevenueContractInformationDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_019d0150-6786-7988-b8f4-8a515a6698bf" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable_019d0150-6786-7791-b55e-63e355fcd59f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_019d0150-6786-7988-b8f4-8a515a6698bf" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable_019d0150-6786-7791-b55e-63e355fcd59f" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionStartDateAxis_019d0150-6786-79aa-97e4-6d817790a895" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionStartDateAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable_019d0150-6786-7791-b55e-63e355fcd59f" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionStartDateAxis_019d0150-6786-79aa-97e4-6d817790a895" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerLiabilityRevenueRecognized_019d0150-6786-7537-8794-00f3566431ea" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ContractWithCustomerLiabilityRevenueRecognized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_019d0150-6786-7988-b8f4-8a515a6698bf" xlink:to="loc_us-gaap_ContractWithCustomerLiabilityRevenueRecognized_019d0150-6786-7537-8794-00f3566431ea" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligation_019d0150-6786-75f4-a07f-357eb04f9159" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RevenueRemainingPerformanceObligation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_019d0150-6786-7988-b8f4-8a515a6698bf" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligation_019d0150-6786-75f4-a07f-357eb04f9159" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1_019d0150-6786-722d-a2a2-17c558d2ba2d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_019d0150-6786-7988-b8f4-8a515a6698bf" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1_019d0150-6786-722d-a2a2-17c558d2ba2d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationPercentage_019d0150-6786-7f76-8009-c29d9d26a699" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RevenueRemainingPerformanceObligationPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_019d0150-6786-7988-b8f4-8a515a6698bf" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligationPercentage_019d0150-6786-7f76-8009-c29d9d26a699" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.cat.com/role/SalesandRevenueContractInformationDetails_1" xlink:type="simple" xlink:href="cat-20260331.xsd#SalesandRevenueContractInformationDetails_1"/>
  <link:definitionLink xlink:role="http://www.cat.com/role/SalesandRevenueContractInformationDetails_1" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_019d0150-6786-7988-b8f4-8a515a6698bf" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable_019d0150-6786-7791-b55e-63e355fcd59f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_019d0150-6786-7988-b8f4-8a515a6698bf" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable_019d0150-6786-7791-b55e-63e355fcd59f" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerLiabilityRevenueRecognized_019d0150-6786-7537-8794-00f3566431ea" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ContractWithCustomerLiabilityRevenueRecognized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_019d0150-6786-7988-b8f4-8a515a6698bf" xlink:to="loc_us-gaap_ContractWithCustomerLiabilityRevenueRecognized_019d0150-6786-7537-8794-00f3566431ea" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligation_019d0150-6786-75f4-a07f-357eb04f9159" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RevenueRemainingPerformanceObligation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_019d0150-6786-7988-b8f4-8a515a6698bf" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligation_019d0150-6786-75f4-a07f-357eb04f9159" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1_019d0150-6786-722d-a2a2-17c558d2ba2d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_019d0150-6786-7988-b8f4-8a515a6698bf" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1_019d0150-6786-722d-a2a2-17c558d2ba2d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationPercentage_019d0150-6786-7f76-8009-c29d9d26a699" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RevenueRemainingPerformanceObligationPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_019d0150-6786-7988-b8f4-8a515a6698bf" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligationPercentage_019d0150-6786-7f76-8009-c29d9d26a699" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.cat.com/role/StockBasedCompensationScheduleofTypeandFairValueofStockBasedCompensationAwardsDetails" xlink:type="simple" xlink:href="cat-20260331.xsd#StockBasedCompensationScheduleofTypeandFairValueofStockBasedCompensationAwardsDetails"/>
  <link:definitionLink xlink:role="http://www.cat.com/role/StockBasedCompensationScheduleofTypeandFairValueofStockBasedCompensationAwardsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019d0150-6786-7e83-9594-bd5aa9a60762" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_019d0150-6786-7a5e-917f-83fcd506cde2" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019d0150-6786-7e83-9594-bd5aa9a60762" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_019d0150-6786-7a5e-917f-83fcd506cde2" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_019d0150-6786-77c9-877c-cfd20176da2a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_019d0150-6786-7a5e-917f-83fcd506cde2" xlink:to="loc_us-gaap_AwardTypeAxis_019d0150-6786-77c9-877c-cfd20176da2a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019d0150-6786-77c9-877c-cfd20176da2a_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_019d0150-6786-77c9-877c-cfd20176da2a" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019d0150-6786-77c9-877c-cfd20176da2a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019d0150-6786-7829-8bb1-058103e0e170" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_019d0150-6786-77c9-877c-cfd20176da2a" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019d0150-6786-7829-8bb1-058103e0e170" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeStockOptionMember_019d0150-6786-7535-be74-7f987c284d03" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EmployeeStockOptionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019d0150-6786-7829-8bb1-058103e0e170" xlink:to="loc_us-gaap_EmployeeStockOptionMember_019d0150-6786-7535-be74-7f987c284d03" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedStockUnitsRSUMember_019d0150-6786-7299-b0aa-6f67228122dd" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RestrictedStockUnitsRSUMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019d0150-6786-7829-8bb1-058103e0e170" xlink:to="loc_us-gaap_RestrictedStockUnitsRSUMember_019d0150-6786-7299-b0aa-6f67228122dd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PerformanceSharesMember_019d0150-6786-7bb3-b3c6-33d33584dd73" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PerformanceSharesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019d0150-6786-7829-8bb1-058103e0e170" xlink:to="loc_us-gaap_PerformanceSharesMember_019d0150-6786-7bb3-b3c6-33d33584dd73" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross_019d0150-6786-7ce4-b674-d8fa1971397b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019d0150-6786-7e83-9594-bd5aa9a60762" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross_019d0150-6786-7ce4-b674-d8fa1971397b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_019d0150-6786-7b67-ae63-8f72d5092ca8" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019d0150-6786-7e83-9594-bd5aa9a60762" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_019d0150-6786-7b67-ae63-8f72d5092ca8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsGranted_019d0150-6786-76eb-b536-d895c05a699c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsGranted"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019d0150-6786-7e83-9594-bd5aa9a60762" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsGranted_019d0150-6786-76eb-b536-d895c05a699c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_019d0150-6786-747b-b0b0-7140c0cd31b2" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019d0150-6786-7e83-9594-bd5aa9a60762" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_019d0150-6786-747b-b0b0-7140c0cd31b2" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.cat.com/role/StockBasedCompensationScheduleofAssumptionsUsedforFairValueDetails" xlink:type="simple" xlink:href="cat-20260331.xsd#StockBasedCompensationScheduleofAssumptionsUsedforFairValueDetails"/>
  <link:definitionLink xlink:role="http://www.cat.com/role/StockBasedCompensationScheduleofAssumptionsUsedforFairValueDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019d0150-6786-7fdf-8b3b-b789fa210406" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_019d0150-6786-7ad3-90c2-e4e75dcaae18" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019d0150-6786-7fdf-8b3b-b789fa210406" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_019d0150-6786-7ad3-90c2-e4e75dcaae18" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_019d0150-6786-71e8-8c2a-8b7fdf39aeef" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_019d0150-6786-7ad3-90c2-e4e75dcaae18" xlink:to="loc_us-gaap_AwardTypeAxis_019d0150-6786-71e8-8c2a-8b7fdf39aeef" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019d0150-6786-71e8-8c2a-8b7fdf39aeef_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_019d0150-6786-71e8-8c2a-8b7fdf39aeef" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019d0150-6786-71e8-8c2a-8b7fdf39aeef_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019d0150-6786-72c4-bac2-f7073bc058da" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_019d0150-6786-71e8-8c2a-8b7fdf39aeef" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019d0150-6786-72c4-bac2-f7073bc058da" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeStockOptionMember_019d0150-6786-75cf-8c84-df88a980a54d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EmployeeStockOptionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019d0150-6786-72c4-bac2-f7073bc058da" xlink:to="loc_us-gaap_EmployeeStockOptionMember_019d0150-6786-75cf-8c84-df88a980a54d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PerformanceSharesMember_019d0150-6786-7c40-84f7-631ddb2867aa" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PerformanceSharesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019d0150-6786-72c4-bac2-f7073bc058da" xlink:to="loc_us-gaap_PerformanceSharesMember_019d0150-6786-7c40-84f7-631ddb2867aa" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate_019d0150-6786-7b07-9c03-928a9ffa9d04" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019d0150-6786-7fdf-8b3b-b789fa210406" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate_019d0150-6786-7b07-9c03-928a9ffa9d04" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsWeightedAverageVolatilityRate_019d0150-6786-7662-9ec6-8b866df7d469" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsWeightedAverageVolatilityRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019d0150-6786-7fdf-8b3b-b789fa210406" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsWeightedAverageVolatilityRate_019d0150-6786-7662-9ec6-8b866df7d469" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRateMinimum_019d0150-6786-703e-a3df-6aaabe6bd8cb" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRateMinimum"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019d0150-6786-7fdf-8b3b-b789fa210406" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRateMinimum_019d0150-6786-703e-a3df-6aaabe6bd8cb" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRateMaximum_019d0150-6786-70b0-adb7-73ffaeac1f29" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRateMaximum"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019d0150-6786-7fdf-8b3b-b789fa210406" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRateMaximum_019d0150-6786-70b0-adb7-73ffaeac1f29" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRateMinimum_019d0150-6786-71af-8576-20a1a724381a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRateMinimum"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019d0150-6786-7fdf-8b3b-b789fa210406" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRateMinimum_019d0150-6786-71af-8576-20a1a724381a" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRateMaximum_019d0150-6786-7c94-8ac1-30387487d0e9" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRateMaximum"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019d0150-6786-7fdf-8b3b-b789fa210406" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRateMaximum_019d0150-6786-7c94-8ac1-30387487d0e9" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1_019d0150-6786-793f-ba8f-6a89d7aba56c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019d0150-6786-7fdf-8b3b-b789fa210406" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1_019d0150-6786-793f-ba8f-6a89d7aba56c" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate_019d0150-6786-7c45-a813-e74918b40161" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019d0150-6786-7fdf-8b3b-b789fa210406" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate_019d0150-6786-7c45-a813-e74918b40161" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate_019d0150-6786-7a25-905c-7268cae58e91" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019d0150-6786-7fdf-8b3b-b789fa210406" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate_019d0150-6786-7a25-905c-7268cae58e91" xlink:type="arc" order="8"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.cat.com/role/DerivativeFinancialinstrumentsandRiskManagementSummaryofLocationandFairValueofDerivativeInstrumentsDetails" xlink:type="simple" xlink:href="cat-20260331.xsd#DerivativeFinancialinstrumentsandRiskManagementSummaryofLocationandFairValueofDerivativeInstrumentsDetails"/>
  <link:definitionLink xlink:role="http://www.cat.com/role/DerivativeFinancialinstrumentsandRiskManagementSummaryofLocationandFairValueofDerivativeInstrumentsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativesFairValueLineItems_019d0150-6786-70f2-9dc2-b977d785fb48" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativesFairValueLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_019d0150-6786-7610-b499-68e2bbbff500" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DerivativesFairValueLineItems_019d0150-6786-70f2-9dc2-b977d785fb48" xlink:to="loc_us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_019d0150-6786-7610-b499-68e2bbbff500" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationAxis_019d0150-6786-7a5a-a459-77aff694e5a4" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_HedgingDesignationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_019d0150-6786-7610-b499-68e2bbbff500" xlink:to="loc_us-gaap_HedgingDesignationAxis_019d0150-6786-7a5a-a459-77aff694e5a4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationDomain_019d0150-6786-7a5a-a459-77aff694e5a4_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_HedgingDesignationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_HedgingDesignationAxis_019d0150-6786-7a5a-a459-77aff694e5a4" xlink:to="loc_us-gaap_HedgingDesignationDomain_019d0150-6786-7a5a-a459-77aff694e5a4_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationDomain_019d0150-6786-787a-b972-7081cddd0483" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_HedgingDesignationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_HedgingDesignationAxis_019d0150-6786-7a5a-a459-77aff694e5a4" xlink:to="loc_us-gaap_HedgingDesignationDomain_019d0150-6786-787a-b972-7081cddd0483" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DesignatedAsHedgingInstrumentMember_019d0150-6786-712c-9a1d-9515ab1b5618" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DesignatedAsHedgingInstrumentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HedgingDesignationDomain_019d0150-6786-787a-b972-7081cddd0483" xlink:to="loc_us-gaap_DesignatedAsHedgingInstrumentMember_019d0150-6786-712c-9a1d-9515ab1b5618" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NondesignatedMember_019d0150-6786-7ee7-906f-601724cedf3b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NondesignatedMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HedgingDesignationDomain_019d0150-6786-787a-b972-7081cddd0483" xlink:to="loc_us-gaap_NondesignatedMember_019d0150-6786-7ee7-906f-601724cedf3b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_019d0150-6786-7b42-bc57-813c9b2c16f3" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeInstrumentRiskAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_019d0150-6786-7610-b499-68e2bbbff500" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_019d0150-6786-7b42-bc57-813c9b2c16f3" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_019d0150-6786-7b42-bc57-813c9b2c16f3_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_019d0150-6786-7b42-bc57-813c9b2c16f3" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_019d0150-6786-7b42-bc57-813c9b2c16f3_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_019d0150-6786-70de-bd32-cc9b13ae0347" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_019d0150-6786-7b42-bc57-813c9b2c16f3" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_019d0150-6786-70de-bd32-cc9b13ae0347" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ForeignExchangeContractMember_019d0150-6786-7335-bda4-fd883682b94e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ForeignExchangeContractMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_019d0150-6786-70de-bd32-cc9b13ae0347" xlink:to="loc_us-gaap_ForeignExchangeContractMember_019d0150-6786-7335-bda4-fd883682b94e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestRateContractMember_019d0150-6786-72d1-acd8-2b5600d5c9ff" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_InterestRateContractMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_019d0150-6786-70de-bd32-cc9b13ae0347" xlink:to="loc_us-gaap_InterestRateContractMember_019d0150-6786-72d1-acd8-2b5600d5c9ff" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommodityContractMember_019d0150-6786-7adf-be02-6c4bd43a6641" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CommodityContractMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_019d0150-6786-70de-bd32-cc9b13ae0347" xlink:to="loc_us-gaap_CommodityContractMember_019d0150-6786-7adf-be02-6c4bd43a6641" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TotalReturnSwapMember_019d0150-6786-766d-81fa-15fe8d08dbf7" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_TotalReturnSwapMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_019d0150-6786-70de-bd32-cc9b13ae0347" xlink:to="loc_us-gaap_TotalReturnSwapMember_019d0150-6786-766d-81fa-15fe8d08dbf7" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeFairValueOfDerivativeAsset_019d0150-6786-7332-996e-fc9a6698229a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeFairValueOfDerivativeAsset"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativesFairValueLineItems_019d0150-6786-70f2-9dc2-b977d785fb48" xlink:to="loc_us-gaap_DerivativeFairValueOfDerivativeAsset_019d0150-6786-7332-996e-fc9a6698229a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeFairValueOfDerivativeLiability_019d0150-6786-7ebf-9823-7e05fcb5c4cc" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeFairValueOfDerivativeLiability"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativesFairValueLineItems_019d0150-6786-70f2-9dc2-b977d785fb48" xlink:to="loc_us-gaap_DerivativeFairValueOfDerivativeLiability_019d0150-6786-7ebf-9823-7e05fcb5c4cc" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.cat.com/role/DerivativeFinancialinstrumentsandRiskManagementScheduleofGainsLossesonDerivativeInstrumentsDetails" xlink:type="simple" xlink:href="cat-20260331.xsd#DerivativeFinancialinstrumentsandRiskManagementScheduleofGainsLossesonDerivativeInstrumentsDetails"/>
  <link:definitionLink xlink:role="http://www.cat.com/role/DerivativeFinancialinstrumentsandRiskManagementScheduleofGainsLossesonDerivativeInstrumentsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentsGainLossLineItems_019d0150-6786-7389-a5c1-a4e8a0403a37" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeInstrumentsGainLossLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable_019d0150-6786-74e0-90d0-ae053fa4fe28" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossLineItems_019d0150-6786-7389-a5c1-a4e8a0403a37" xlink:to="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable_019d0150-6786-74e0-90d0-ae053fa4fe28" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationAxis_019d0150-6786-7983-b3e0-447a0111f598" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_HedgingDesignationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable_019d0150-6786-74e0-90d0-ae053fa4fe28" xlink:to="loc_us-gaap_HedgingDesignationAxis_019d0150-6786-7983-b3e0-447a0111f598" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationDomain_019d0150-6786-7983-b3e0-447a0111f598_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_HedgingDesignationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_HedgingDesignationAxis_019d0150-6786-7983-b3e0-447a0111f598" xlink:to="loc_us-gaap_HedgingDesignationDomain_019d0150-6786-7983-b3e0-447a0111f598_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationDomain_019d0150-6786-7e64-bf92-3a0d3d06cbc4" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_HedgingDesignationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_HedgingDesignationAxis_019d0150-6786-7983-b3e0-447a0111f598" xlink:to="loc_us-gaap_HedgingDesignationDomain_019d0150-6786-7e64-bf92-3a0d3d06cbc4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DesignatedAsHedgingInstrumentMember_019d0150-6786-79ef-8049-a3941a57c9db" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DesignatedAsHedgingInstrumentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HedgingDesignationDomain_019d0150-6786-7e64-bf92-3a0d3d06cbc4" xlink:to="loc_us-gaap_DesignatedAsHedgingInstrumentMember_019d0150-6786-79ef-8049-a3941a57c9db" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NondesignatedMember_019d0150-6786-724a-8fe0-6a8a15d3ab90" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NondesignatedMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HedgingDesignationDomain_019d0150-6786-7e64-bf92-3a0d3d06cbc4" xlink:to="loc_us-gaap_NondesignatedMember_019d0150-6786-724a-8fe0-6a8a15d3ab90" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_019d0150-6786-72e5-bc79-e75369b55264" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable_019d0150-6786-74e0-90d0-ae053fa4fe28" xlink:to="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_019d0150-6786-72e5-bc79-e75369b55264" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingRelationshipDomain_019d0150-6786-72e5-bc79-e75369b55264_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_HedgingRelationshipDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_019d0150-6786-72e5-bc79-e75369b55264" xlink:to="loc_us-gaap_HedgingRelationshipDomain_019d0150-6786-72e5-bc79-e75369b55264_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingRelationshipDomain_019d0150-6786-79a4-88d6-be9963d544cf" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_HedgingRelationshipDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_019d0150-6786-72e5-bc79-e75369b55264" xlink:to="loc_us-gaap_HedgingRelationshipDomain_019d0150-6786-79a4-88d6-be9963d544cf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashFlowHedgingMember_019d0150-6786-7dc2-a0f0-877578cdffc7" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CashFlowHedgingMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HedgingRelationshipDomain_019d0150-6786-79a4-88d6-be9963d544cf" xlink:to="loc_us-gaap_CashFlowHedgingMember_019d0150-6786-7dc2-a0f0-877578cdffc7" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueHedgingMember_019d0150-6786-7d73-9b36-786fe00bb2ce" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueHedgingMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HedgingRelationshipDomain_019d0150-6786-79a4-88d6-be9963d544cf" xlink:to="loc_us-gaap_FairValueHedgingMember_019d0150-6786-7d73-9b36-786fe00bb2ce" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_019d0150-6786-7994-83c3-5daec5618d07" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeInstrumentRiskAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable_019d0150-6786-74e0-90d0-ae053fa4fe28" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_019d0150-6786-7994-83c3-5daec5618d07" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_019d0150-6786-7994-83c3-5daec5618d07_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_019d0150-6786-7994-83c3-5daec5618d07" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_019d0150-6786-7994-83c3-5daec5618d07_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_019d0150-6786-7e5f-8706-10682109d8aa" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_019d0150-6786-7994-83c3-5daec5618d07" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_019d0150-6786-7e5f-8706-10682109d8aa" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ForeignExchangeContractMember_019d0150-6786-7625-9c98-d99de511a530" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ForeignExchangeContractMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_019d0150-6786-7e5f-8706-10682109d8aa" xlink:to="loc_us-gaap_ForeignExchangeContractMember_019d0150-6786-7625-9c98-d99de511a530" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestRateContractMember_019d0150-6786-763d-aeab-a962c496a118" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_InterestRateContractMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_019d0150-6786-7e5f-8706-10682109d8aa" xlink:to="loc_us-gaap_InterestRateContractMember_019d0150-6786-763d-aeab-a962c496a118" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommodityContractMember_019d0150-6786-7f48-bfbc-360ac3a06ce7" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CommodityContractMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_019d0150-6786-7e5f-8706-10682109d8aa" xlink:to="loc_us-gaap_CommodityContractMember_019d0150-6786-7f48-bfbc-360ac3a06ce7" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TotalReturnSwapMember_019d0150-6786-7936-8f7d-c2b2549b800c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_TotalReturnSwapMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_019d0150-6786-7e5f-8706-10682109d8aa" xlink:to="loc_us-gaap_TotalReturnSwapMember_019d0150-6786-7936-8f7d-c2b2549b800c" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainLossOnDerivativeInstrumentsNetPretax_019d0150-6786-7634-b6e7-6332e97c07fc" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_GainLossOnDerivativeInstrumentsNetPretax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossLineItems_019d0150-6786-7389-a5c1-a4e8a0403a37" xlink:to="loc_us-gaap_GainLossOnDerivativeInstrumentsNetPretax_019d0150-6786-7634-b6e7-6332e97c07fc" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAndTax_019d0150-6786-71cc-9ebd-94b7c0133260" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAndTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossLineItems_019d0150-6786-7389-a5c1-a4e8a0403a37" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAndTax_019d0150-6786-71cc-9ebd-94b7c0133260" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossReclassificationBeforeTax_019d0150-6786-7c28-b20e-dbb26cb1c9ed" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossReclassificationBeforeTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossLineItems_019d0150-6786-7389-a5c1-a4e8a0403a37" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossReclassificationBeforeTax_019d0150-6786-7c28-b20e-dbb26cb1c9ed" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.cat.com/role/DerivativeFinancialInstrumentsandRiskManagementSummaryofCumulativeBasisAdjustmentsforFairValueHedgesDetails" xlink:type="simple" xlink:href="cat-20260331.xsd#DerivativeFinancialInstrumentsandRiskManagementSummaryofCumulativeBasisAdjustmentsforFairValueHedgesDetails"/>
  <link:definitionLink xlink:role="http://www.cat.com/role/DerivativeFinancialInstrumentsandRiskManagementSummaryofCumulativeBasisAdjustmentsforFairValueHedgesDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativesFairValueLineItems_019d0150-6786-71fe-8eb4-4294ff889d0a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativesFairValueLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_019d0150-6786-7d8f-8a3c-1994e0cd5ed4" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DerivativesFairValueLineItems_019d0150-6786-71fe-8eb4-4294ff889d0a" xlink:to="loc_us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_019d0150-6786-7d8f-8a3c-1994e0cd5ed4" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationAxis_019d0150-6786-7bfc-82f5-a44ce991d8c3" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BalanceSheetLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_019d0150-6786-7d8f-8a3c-1994e0cd5ed4" xlink:to="loc_us-gaap_BalanceSheetLocationAxis_019d0150-6786-7bfc-82f5-a44ce991d8c3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_019d0150-6786-7bfc-82f5-a44ce991d8c3_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_019d0150-6786-7bfc-82f5-a44ce991d8c3" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_019d0150-6786-7bfc-82f5-a44ce991d8c3_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_019d0150-6786-757b-9228-cfe64731f5ec" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_019d0150-6786-7bfc-82f5-a44ce991d8c3" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_019d0150-6786-757b-9228-cfe64731f5ec" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_LongTermDebtDueWithinOneYearMember_019d0150-6786-716a-83a3-105faaa4d161" xlink:href="cat-20260331.xsd#cat_LongTermDebtDueWithinOneYearMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_019d0150-6786-757b-9228-cfe64731f5ec" xlink:to="loc_cat_LongTermDebtDueWithinOneYearMember_019d0150-6786-716a-83a3-105faaa4d161" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_LongTermDebtDueAfterOneYearMember_019d0150-6786-721a-b8a9-4ba2d509f947" xlink:href="cat-20260331.xsd#cat_LongTermDebtDueAfterOneYearMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_019d0150-6786-757b-9228-cfe64731f5ec" xlink:to="loc_cat_LongTermDebtDueAfterOneYearMember_019d0150-6786-721a-b8a9-4ba2d509f947" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgedLiabilityFairValueHedge_019d0150-6786-7b63-b314-95cf84d5e6bb" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_HedgedLiabilityFairValueHedge"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativesFairValueLineItems_019d0150-6786-71fe-8eb4-4294ff889d0a" xlink:to="loc_us-gaap_HedgedLiabilityFairValueHedge_019d0150-6786-7b63-b314-95cf84d5e6bb" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgedLiabilityFairValueHedgeCumulativeIncreaseDecrease_019d0150-6786-7382-b77a-a5d2bbd2a89f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_HedgedLiabilityFairValueHedgeCumulativeIncreaseDecrease"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativesFairValueLineItems_019d0150-6786-71fe-8eb4-4294ff889d0a" xlink:to="loc_us-gaap_HedgedLiabilityFairValueHedgeCumulativeIncreaseDecrease_019d0150-6786-7382-b77a-a5d2bbd2a89f" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.cat.com/role/IntangibleAssetsandGoodwillSummaryofIntangibleAssetsDetails" xlink:type="simple" xlink:href="cat-20260331.xsd#IntangibleAssetsandGoodwillSummaryofIntangibleAssetsDetails"/>
  <link:definitionLink xlink:role="http://www.cat.com/role/IntangibleAssetsandGoodwillSummaryofIntangibleAssetsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_019d0150-6786-7d91-8762-258baf9f4f60" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FiniteLivedIntangibleAssetsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_019d0150-6786-79f7-a211-5428fa7fcf3a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_019d0150-6786-7d91-8762-258baf9f4f60" xlink:to="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_019d0150-6786-79f7-a211-5428fa7fcf3a" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_019d0150-6786-7630-b684-ac4ca3a79bda" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_019d0150-6786-79f7-a211-5428fa7fcf3a" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_019d0150-6786-7630-b684-ac4ca3a79bda" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_019d0150-6786-7630-b684-ac4ca3a79bda_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_019d0150-6786-7630-b684-ac4ca3a79bda" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_019d0150-6786-7630-b684-ac4ca3a79bda_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_019d0150-6786-7b35-be43-bfa117de238f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_019d0150-6786-7630-b684-ac4ca3a79bda" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_019d0150-6786-7b35-be43-bfa117de238f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CustomerRelationshipsMember_019d0150-6786-7468-ae2c-1b031385e6d7" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CustomerRelationshipsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_019d0150-6786-7b35-be43-bfa117de238f" xlink:to="loc_us-gaap_CustomerRelationshipsMember_019d0150-6786-7468-ae2c-1b031385e6d7" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DevelopedTechnologyRightsMember_019d0150-6786-7ff7-98a2-6bec08a8c968" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DevelopedTechnologyRightsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_019d0150-6786-7b35-be43-bfa117de238f" xlink:to="loc_us-gaap_DevelopedTechnologyRightsMember_019d0150-6786-7ff7-98a2-6bec08a8c968" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherIntangibleAssetsMember_019d0150-6786-7da7-b39c-5dc6aa83385d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherIntangibleAssetsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_019d0150-6786-7b35-be43-bfa117de238f" xlink:to="loc_us-gaap_OtherIntangibleAssetsMember_019d0150-6786-7da7-b39c-5dc6aa83385d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsGross_019d0150-6786-73f7-95e8-bad54171ec12" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FiniteLivedIntangibleAssetsGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_019d0150-6786-7d91-8762-258baf9f4f60" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsGross_019d0150-6786-73f7-95e8-bad54171ec12" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_019d0150-6786-7e55-b4f8-17939c0fd2c6" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_019d0150-6786-7d91-8762-258baf9f4f60" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_019d0150-6786-7e55-b4f8-17939c0fd2c6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsNet_019d0150-6786-7854-a470-1eb1a8d04fb3" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FiniteLivedIntangibleAssetsNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_019d0150-6786-7d91-8762-258baf9f4f60" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsNet_019d0150-6786-7854-a470-1eb1a8d04fb3" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.cat.com/role/IntangibleAssetsandGoodwillSummaryofGoodwillAcquiredDetails" xlink:type="simple" xlink:href="cat-20260331.xsd#IntangibleAssetsandGoodwillSummaryofGoodwillAcquiredDetails"/>
  <link:definitionLink xlink:role="http://www.cat.com/role/IntangibleAssetsandGoodwillSummaryofGoodwillAcquiredDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillLineItems_019d0150-6786-77b5-b7c6-aec54087a2ac" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_GoodwillLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfGoodwillTable_019d0150-6786-726b-a88f-7a04df43d008" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfGoodwillTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_GoodwillLineItems_019d0150-6786-77b5-b7c6-aec54087a2ac" xlink:to="loc_us-gaap_ScheduleOfGoodwillTable_019d0150-6786-726b-a88f-7a04df43d008" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_019d0150-6786-7fea-bbb5-ffbf121029fc" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfGoodwillTable_019d0150-6786-726b-a88f-7a04df43d008" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_019d0150-6786-7fea-bbb5-ffbf121029fc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_019d0150-6786-7fea-bbb5-ffbf121029fc_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_019d0150-6786-7fea-bbb5-ffbf121029fc" xlink:to="loc_us-gaap_SegmentDomain_019d0150-6786-7fea-bbb5-ffbf121029fc_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_019d0150-6786-7cd6-9c48-509acf209339" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_019d0150-6786-7fea-bbb5-ffbf121029fc" xlink:to="loc_us-gaap_SegmentDomain_019d0150-6786-7cd6-9c48-509acf209339" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_ConstructionIndustriesMember_019d0150-6786-79d1-91ab-eaf8a6df9bec" xlink:href="cat-20260331.xsd#cat_ConstructionIndustriesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019d0150-6786-7cd6-9c48-509acf209339" xlink:to="loc_cat_ConstructionIndustriesMember_019d0150-6786-79d1-91ab-eaf8a6df9bec" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_ResourceIndustriesMember_019d0150-6786-73b5-9136-e7b42ef29f91" xlink:href="cat-20260331.xsd#cat_ResourceIndustriesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019d0150-6786-7cd6-9c48-509acf209339" xlink:to="loc_cat_ResourceIndustriesMember_019d0150-6786-73b5-9136-e7b42ef29f91" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_PowerEnergyMember_019d0150-6786-7897-8c71-1cb075aa629b" xlink:href="cat-20260331.xsd#cat_PowerEnergyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019d0150-6786-7cd6-9c48-509acf209339" xlink:to="loc_cat_PowerEnergyMember_019d0150-6786-7897-8c71-1cb075aa629b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllOtherSegmentsMember_019d0150-6786-7875-8b60-ed626851f770" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AllOtherSegmentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019d0150-6786-7cd6-9c48-509acf209339" xlink:to="loc_us-gaap_AllOtherSegmentsMember_019d0150-6786-7875-8b60-ed626851f770" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillGross_019d0150-6786-7217-8ba1-0b4ecae3317d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_GoodwillGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GoodwillLineItems_019d0150-6786-77b5-b7c6-aec54087a2ac" xlink:to="loc_us-gaap_GoodwillGross_019d0150-6786-7217-8ba1-0b4ecae3317d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillImpairedAccumulatedImpairmentLoss_019d0150-6786-7641-a87e-a308e15278f9" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_GoodwillImpairedAccumulatedImpairmentLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GoodwillLineItems_019d0150-6786-77b5-b7c6-aec54087a2ac" xlink:to="loc_us-gaap_GoodwillImpairedAccumulatedImpairmentLoss_019d0150-6786-7641-a87e-a308e15278f9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Goodwill_019d0150-6786-7650-8ff5-1e3281cebec5" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_Goodwill"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GoodwillLineItems_019d0150-6786-77b5-b7c6-aec54087a2ac" xlink:to="loc_us-gaap_Goodwill_019d0150-6786-7650-8ff5-1e3281cebec5" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillRollForward_019d0150-6786-7b34-8027-ae6fd4f42072" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_GoodwillRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GoodwillLineItems_019d0150-6786-77b5-b7c6-aec54087a2ac" xlink:to="loc_us-gaap_GoodwillRollForward_019d0150-6786-7b34-8027-ae6fd4f42072" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillGross_019d0150-6786-7949-a538-5d99f474c2a5" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_GoodwillGross"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillAcquiredDuringPeriod_019d92ba-548b-7f1c-a1a5-cdc5a62eb768" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_GoodwillAcquiredDuringPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GoodwillRollForward_019d0150-6786-7b34-8027-ae6fd4f42072" xlink:to="loc_us-gaap_GoodwillAcquiredDuringPeriod_019d92ba-548b-7f1c-a1a5-cdc5a62eb768" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillTranslationAndPurchaseAccountingAdjustments_019d0150-6786-7ab7-b25b-7efc9ebd0da6" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_GoodwillTranslationAndPurchaseAccountingAdjustments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GoodwillRollForward_019d0150-6786-7b34-8027-ae6fd4f42072" xlink:to="loc_us-gaap_GoodwillTranslationAndPurchaseAccountingAdjustments_019d0150-6786-7ab7-b25b-7efc9ebd0da6" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillGross_019d0150-6786-7b09-8f57-014827e42755" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_GoodwillGross"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Goodwill_019d0150-6786-7dc8-9bef-2a6bfe9726ad" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_Goodwill"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillAcquiredDuringPeriod_019d92bb-1165-7dd9-a219-36740b1d91e6" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_GoodwillAcquiredDuringPeriod"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillTranslationAndPurchaseAccountingAdjustments_019d0150-6786-7642-8f3e-47b18041093f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_GoodwillTranslationAndPurchaseAccountingAdjustments"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Goodwill_019d0150-6786-7aed-bb3d-b828a99828de" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_Goodwill"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.cat.com/role/InvestmentsinDebtandEquitySecuritiesScheduleofCostBasisandFairValueofAvailableforSaleSecuritiesDetails" xlink:type="simple" xlink:href="cat-20260331.xsd#InvestmentsinDebtandEquitySecuritiesScheduleofCostBasisandFairValueofAvailableforSaleSecuritiesDetails"/>
  <link:definitionLink xlink:role="http://www.cat.com/role/InvestmentsinDebtandEquitySecuritiesScheduleofCostBasisandFairValueofAvailableforSaleSecuritiesDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_019d0150-6786-728d-90ff-2b3228cd3a39" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleTable_019d0150-6786-7995-8929-b67203d8a330" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtSecuritiesAvailableForSaleTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_019d0150-6786-728d-90ff-2b3228cd3a39" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleTable_019d0150-6786-7995-8929-b67203d8a330" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentAxis_019d0150-6786-740c-9c9b-a125c161fb88" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancialInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtSecuritiesAvailableForSaleTable_019d0150-6786-7995-8929-b67203d8a330" xlink:to="loc_us-gaap_FinancialInstrumentAxis_019d0150-6786-740c-9c9b-a125c161fb88" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019d0150-6786-740c-9c9b-a125c161fb88_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentAxis_019d0150-6786-740c-9c9b-a125c161fb88" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019d0150-6786-740c-9c9b-a125c161fb88_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019d0150-6786-7a58-b6ba-82ac7db25579" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentAxis_019d0150-6786-740c-9c9b-a125c161fb88" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019d0150-6786-7a58-b6ba-82ac7db25579" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_USTreasurySecuritiesMember_019d0150-6786-73af-91b3-015183dcd6de" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_USTreasurySecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019d0150-6786-7a58-b6ba-82ac7db25579" xlink:to="loc_us-gaap_USTreasurySecuritiesMember_019d0150-6786-73af-91b3-015183dcd6de" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_OtherUSGovernmentAndNonUSGovernmentDebtMember_019d0150-6786-7770-ad4b-f9357dc153fe" xlink:href="cat-20260331.xsd#cat_OtherUSGovernmentAndNonUSGovernmentDebtMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019d0150-6786-7a58-b6ba-82ac7db25579" xlink:to="loc_cat_OtherUSGovernmentAndNonUSGovernmentDebtMember_019d0150-6786-7770-ad4b-f9357dc153fe" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CorporateBondSecuritiesMember_019d0150-6786-737d-82b7-636238e7e942" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CorporateBondSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019d0150-6786-7a58-b6ba-82ac7db25579" xlink:to="loc_us-gaap_CorporateBondSecuritiesMember_019d0150-6786-737d-82b7-636238e7e942" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetBackedSecuritiesMember_019d0150-6786-7703-9f4d-5b0c25c46fe7" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AssetBackedSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019d0150-6786-7a58-b6ba-82ac7db25579" xlink:to="loc_us-gaap_AssetBackedSecuritiesMember_019d0150-6786-7703-9f4d-5b0c25c46fe7" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember_019d0150-6786-78f5-b6e2-b05cddd86edd" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019d0150-6786-7a58-b6ba-82ac7db25579" xlink:to="loc_us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember_019d0150-6786-78f5-b6e2-b05cddd86edd" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ResidentialMortgageBackedSecuritiesMember_019d0150-6786-7055-86f0-5a89d8da8b9d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ResidentialMortgageBackedSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019d0150-6786-7a58-b6ba-82ac7db25579" xlink:to="loc_us-gaap_ResidentialMortgageBackedSecuritiesMember_019d0150-6786-7055-86f0-5a89d8da8b9d" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialMortgageBackedSecuritiesMember_019d0150-6786-7309-8df5-6344c010d2ff" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CommercialMortgageBackedSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019d0150-6786-7a58-b6ba-82ac7db25579" xlink:to="loc_us-gaap_CommercialMortgageBackedSecuritiesMember_019d0150-6786-7309-8df5-6344c010d2ff" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis_019d0150-6786-724b-9247-1ef79dd27bb0" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_019d0150-6786-728d-90ff-2b3228cd3a39" xlink:to="loc_us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis_019d0150-6786-724b-9247-1ef79dd27bb0" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleAccumulatedGrossUnrealizedGainLossBeforeTax_019d0150-6786-7108-8da7-6de9335ba188" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtSecuritiesAvailableForSaleAccumulatedGrossUnrealizedGainLossBeforeTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_019d0150-6786-728d-90ff-2b3228cd3a39" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleAccumulatedGrossUnrealizedGainLossBeforeTax_019d0150-6786-7108-8da7-6de9335ba188" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtSecurities_019d0150-6786-7cbd-a160-ff7c2eb0daf5" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AvailableForSaleSecuritiesDebtSecurities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_019d0150-6786-728d-90ff-2b3228cd3a39" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtSecurities_019d0150-6786-7cbd-a160-ff7c2eb0daf5" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.cat.com/role/InvestmentsinDebtandEquitySecuritiesSummaryofInvestmentsInAnUnrealizedLossPositionThatAreNotOtherThanTemporarilyImpairedDetails" xlink:type="simple" xlink:href="cat-20260331.xsd#InvestmentsinDebtandEquitySecuritiesSummaryofInvestmentsInAnUnrealizedLossPositionThatAreNotOtherThanTemporarilyImpairedDetails"/>
  <link:definitionLink xlink:role="http://www.cat.com/role/InvestmentsinDebtandEquitySecuritiesSummaryofInvestmentsInAnUnrealizedLossPositionThatAreNotOtherThanTemporarilyImpairedDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValueAbstract_019d0150-6786-7a74-adcf-aa0f5e1b724b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValueAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionFairValueTable_019d0150-6786-787a-84f8-202951ea328e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionFairValueTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValueAbstract_019d0150-6786-7a74-adcf-aa0f5e1b724b" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionFairValueTable_019d0150-6786-787a-84f8-202951ea328e" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentAxis_019d0150-6786-7902-9101-7e3c9472367f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancialInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionFairValueTable_019d0150-6786-787a-84f8-202951ea328e" xlink:to="loc_us-gaap_FinancialInstrumentAxis_019d0150-6786-7902-9101-7e3c9472367f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019d0150-6786-7902-9101-7e3c9472367f_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentAxis_019d0150-6786-7902-9101-7e3c9472367f" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019d0150-6786-7902-9101-7e3c9472367f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019d0150-6786-7d0d-b11f-1a27126ea0b7" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentAxis_019d0150-6786-7902-9101-7e3c9472367f" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019d0150-6786-7d0d-b11f-1a27126ea0b7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_OtherUSGovernmentAndNonUSGovernmentDebtMember_019d0150-6786-7dc8-8eba-967fcb828082" xlink:href="cat-20260331.xsd#cat_OtherUSGovernmentAndNonUSGovernmentDebtMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019d0150-6786-7d0d-b11f-1a27126ea0b7" xlink:to="loc_cat_OtherUSGovernmentAndNonUSGovernmentDebtMember_019d0150-6786-7dc8-8eba-967fcb828082" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CorporateBondSecuritiesMember_019d0150-6786-7d1c-94cc-66e54d9c94e2" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CorporateBondSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019d0150-6786-7d0d-b11f-1a27126ea0b7" xlink:to="loc_us-gaap_CorporateBondSecuritiesMember_019d0150-6786-7d1c-94cc-66e54d9c94e2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetBackedSecuritiesMember_019d0150-6786-7ed1-8bfb-11b01a1f05d2" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AssetBackedSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019d0150-6786-7d0d-b11f-1a27126ea0b7" xlink:to="loc_us-gaap_AssetBackedSecuritiesMember_019d0150-6786-7ed1-8bfb-11b01a1f05d2" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember_019d0150-6786-76a7-9562-cb0245294735" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019d0150-6786-7d0d-b11f-1a27126ea0b7" xlink:to="loc_us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember_019d0150-6786-76a7-9562-cb0245294735" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ResidentialMortgageBackedSecuritiesMember_019d0150-6786-70bb-bce2-03f2e2224ab8" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ResidentialMortgageBackedSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019d0150-6786-7d0d-b11f-1a27126ea0b7" xlink:to="loc_us-gaap_ResidentialMortgageBackedSecuritiesMember_019d0150-6786-70bb-bce2-03f2e2224ab8" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialMortgageBackedSecuritiesMember_019d0150-6786-787e-8604-9ac150983af7" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CommercialMortgageBackedSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019d0150-6786-7d0d-b11f-1a27126ea0b7" xlink:to="loc_us-gaap_CommercialMortgageBackedSecuritiesMember_019d0150-6786-787e-8604-9ac150983af7" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months_019d0150-6786-79e7-a9b9-521e2116c6fe" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValueAbstract_019d0150-6786-7a74-adcf-aa0f5e1b724b" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months_019d0150-6786-79e7-a9b9-521e2116c6fe" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss_019d0150-6786-7445-9d6a-e5da6a82810a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValueAbstract_019d0150-6786-7a74-adcf-aa0f5e1b724b" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss_019d0150-6786-7445-9d6a-e5da6a82810a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger_019d0150-6786-7753-b5e0-a1b67652c92d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValueAbstract_019d0150-6786-7a74-adcf-aa0f5e1b724b" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger_019d0150-6786-7753-b5e0-a1b67652c92d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss_019d0150-6786-7b56-93bf-7be169fd004e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValueAbstract_019d0150-6786-7a74-adcf-aa0f5e1b724b" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss_019d0150-6786-7b56-93bf-7be169fd004e" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPosition_019d0150-6786-7ee4-b818-7525255cb5df" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPosition"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValueAbstract_019d0150-6786-7a74-adcf-aa0f5e1b724b" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPosition_019d0150-6786-7ee4-b818-7525255cb5df" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss_019d0150-6786-7a7a-85f1-3639e4367dbc" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValueAbstract_019d0150-6786-7a74-adcf-aa0f5e1b724b" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss_019d0150-6786-7a7a-85f1-3639e4367dbc" xlink:type="arc" order="5"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.cat.com/role/InvestmentsinDebtandEquitySecuritiesSummaryofCostBasisAndFairValueOfTheAvailableForSaleDebtSecuritiesByContractualMaturityDetails" xlink:type="simple" xlink:href="cat-20260331.xsd#InvestmentsinDebtandEquitySecuritiesSummaryofCostBasisAndFairValueOfTheAvailableForSaleDebtSecuritiesByContractualMaturityDetails"/>
  <link:definitionLink xlink:role="http://www.cat.com/role/InvestmentsinDebtandEquitySecuritiesSummaryofCostBasisAndFairValueOfTheAvailableForSaleDebtSecuritiesByContractualMaturityDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_019d0150-683a-7f92-9c66-75d6801132a2" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleTable_019d0150-683a-7282-90c8-59001a533ac7" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtSecuritiesAvailableForSaleTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_019d0150-683a-7f92-9c66-75d6801132a2" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleTable_019d0150-683a-7282-90c8-59001a533ac7" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentAxis_019d0150-683a-704f-b9cf-0a562fc25f38" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancialInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtSecuritiesAvailableForSaleTable_019d0150-683a-7282-90c8-59001a533ac7" xlink:to="loc_us-gaap_FinancialInstrumentAxis_019d0150-683a-704f-b9cf-0a562fc25f38" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019d0150-683a-704f-b9cf-0a562fc25f38_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentAxis_019d0150-683a-704f-b9cf-0a562fc25f38" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019d0150-683a-704f-b9cf-0a562fc25f38_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019d0150-683a-7150-9a79-a7c0a16b2585" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentAxis_019d0150-683a-704f-b9cf-0a562fc25f38" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019d0150-683a-7150-9a79-a7c0a16b2585" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember_019d0150-683a-77c6-9a44-e207f24cc162" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019d0150-683a-7150-9a79-a7c0a16b2585" xlink:to="loc_us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember_019d0150-683a-77c6-9a44-e207f24cc162" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ResidentialMortgageBackedSecuritiesMember_019d0150-683a-7a43-90dc-5b61a934198a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ResidentialMortgageBackedSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019d0150-683a-7150-9a79-a7c0a16b2585" xlink:to="loc_us-gaap_ResidentialMortgageBackedSecuritiesMember_019d0150-683a-7a43-90dc-5b61a934198a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialMortgageBackedSecuritiesMember_019d0150-683a-70eb-8ad2-e527c090188b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CommercialMortgageBackedSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019d0150-683a-7150-9a79-a7c0a16b2585" xlink:to="loc_us-gaap_CommercialMortgageBackedSecuritiesMember_019d0150-683a-70eb-8ad2-e527c090188b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAmortizedCostAbstract_019d0150-683a-7924-b44e-c9d9d11e4d85" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAmortizedCostAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_019d0150-683a-7f92-9c66-75d6801132a2" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAmortizedCostAbstract_019d0150-683a-7924-b44e-c9d9d11e4d85" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearAmortizedCost_019d0150-683a-745d-b28c-397d7a358d9e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearAmortizedCost"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAmortizedCostAbstract_019d0150-683a-7924-b44e-c9d9d11e4d85" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearAmortizedCost_019d0150-683a-745d-b28c-397d7a358d9e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsAmortizedCost_019d0150-683a-7b77-be28-f9043ce4c747" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsAmortizedCost"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAmortizedCostAbstract_019d0150-683a-7924-b44e-c9d9d11e4d85" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsAmortizedCost_019d0150-683a-7b77-be28-f9043ce4c747" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsAmortizedCost_019d0150-683a-7c47-bdd6-c03f33bba1d8" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsAmortizedCost"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAmortizedCostAbstract_019d0150-683a-7924-b44e-c9d9d11e4d85" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsAmortizedCost_019d0150-683a-7c47-bdd6-c03f33bba1d8" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsAmortizedCost_019d0150-683a-74d5-acce-229c8857608e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsAmortizedCost"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAmortizedCostAbstract_019d0150-683a-7924-b44e-c9d9d11e4d85" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsAmortizedCost_019d0150-683a-74d5-acce-229c8857608e" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis_019d0150-683a-7e11-9316-df759e3d84c3" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAmortizedCostAbstract_019d0150-683a-7924-b44e-c9d9d11e4d85" xlink:to="loc_us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis_019d0150-683a-7e11-9316-df759e3d84c3" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesFairValueAbstract_019d0150-683a-738a-8946-e16d47e1854b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesFairValueAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_019d0150-683a-7f92-9c66-75d6801132a2" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesFairValueAbstract_019d0150-683a-738a-8946-e16d47e1854b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearFairValue_019d0150-683a-7667-b9eb-381a9ad735e8" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesFairValueAbstract_019d0150-683a-738a-8946-e16d47e1854b" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearFairValue_019d0150-683a-7667-b9eb-381a9ad735e8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsFairValue_019d0150-683a-787e-954c-321b35738998" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesFairValueAbstract_019d0150-683a-738a-8946-e16d47e1854b" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsFairValue_019d0150-683a-787e-954c-321b35738998" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsFairValue_019d0150-683a-71b2-992b-5cf436768885" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesFairValueAbstract_019d0150-683a-738a-8946-e16d47e1854b" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsFairValue_019d0150-683a-71b2-992b-5cf436768885" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsFairValue_019d0150-683a-7ac6-98c3-1b2ef5aa02f5" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesFairValueAbstract_019d0150-683a-738a-8946-e16d47e1854b" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsFairValue_019d0150-683a-7ac6-98c3-1b2ef5aa02f5" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtSecurities_019d0150-683a-77df-aac3-1e2200f14b47" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AvailableForSaleSecuritiesDebtSecurities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesFairValueAbstract_019d0150-683a-738a-8946-e16d47e1854b" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtSecurities_019d0150-683a-77df-aac3-1e2200f14b47" xlink:type="arc" order="5"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.cat.com/role/PostretirementBenefitsScheduleOfNetBenefitCostsDetails" xlink:type="simple" xlink:href="cat-20260331.xsd#PostretirementBenefitsScheduleOfNetBenefitCostsDetails"/>
  <link:definitionLink xlink:role="http://www.cat.com/role/PostretirementBenefitsScheduleOfNetBenefitCostsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_019d0150-683a-7ae3-b835-2b885b4e623c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanDisclosureLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_019d0150-683a-7398-ac5a-3422f9b63110" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_019d0150-683a-7ae3-b835-2b885b4e623c" xlink:to="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_019d0150-683a-7398-ac5a-3422f9b63110" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeAxis_019d0150-683a-7eb3-b094-e002e557af15" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RetirementPlanTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_019d0150-683a-7398-ac5a-3422f9b63110" xlink:to="loc_us-gaap_RetirementPlanTypeAxis_019d0150-683a-7eb3-b094-e002e557af15" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_019d0150-683a-7eb3-b094-e002e557af15_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RetirementPlanTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_019d0150-683a-7eb3-b094-e002e557af15" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_019d0150-683a-7eb3-b094-e002e557af15_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_019d0150-683a-7e14-bcf8-a9a11b38575a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RetirementPlanTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_019d0150-683a-7eb3-b094-e002e557af15" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_019d0150-683a-7e14-bcf8-a9a11b38575a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PensionPlansDefinedBenefitMember_019d0150-683a-7235-b56f-aecc2c630eb2" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PensionPlansDefinedBenefitMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanTypeDomain_019d0150-683a-7e14-bcf8-a9a11b38575a" xlink:to="loc_us-gaap_PensionPlansDefinedBenefitMember_019d0150-683a-7235-b56f-aecc2c630eb2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember_019d0150-683a-7ada-a2ac-133d50595fbb" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanTypeDomain_019d0150-683a-7e14-bcf8-a9a11b38575a" xlink:to="loc_us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember_019d0150-683a-7ada-a2ac-133d50595fbb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanSponsorLocationAxis_019d0150-683a-7d5a-85d1-73f95150ec2f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RetirementPlanSponsorLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_019d0150-683a-7398-ac5a-3422f9b63110" xlink:to="loc_us-gaap_RetirementPlanSponsorLocationAxis_019d0150-683a-7d5a-85d1-73f95150ec2f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanSponsorLocationDomain_019d0150-683a-7d5a-85d1-73f95150ec2f_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RetirementPlanSponsorLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RetirementPlanSponsorLocationAxis_019d0150-683a-7d5a-85d1-73f95150ec2f" xlink:to="loc_us-gaap_RetirementPlanSponsorLocationDomain_019d0150-683a-7d5a-85d1-73f95150ec2f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanSponsorLocationDomain_019d0150-683a-7738-ab9c-7f9c2380ce6c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RetirementPlanSponsorLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RetirementPlanSponsorLocationAxis_019d0150-683a-7d5a-85d1-73f95150ec2f" xlink:to="loc_us-gaap_RetirementPlanSponsorLocationDomain_019d0150-683a-7738-ab9c-7f9c2380ce6c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DomesticPlanMember_019d0150-683a-7915-a880-6e9052fc58d1" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DomesticPlanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanSponsorLocationDomain_019d0150-683a-7738-ab9c-7f9c2380ce6c" xlink:to="loc_us-gaap_DomesticPlanMember_019d0150-683a-7915-a880-6e9052fc58d1" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_country_US_019d0150-683a-7909-8cca-52640f28766b" xlink:href="https://xbrl.sec.gov/country/2025/country-2025.xsd#country_US"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DomesticPlanMember_019d0150-683a-7915-a880-6e9052fc58d1" xlink:to="loc_country_US_019d0150-683a-7909-8cca-52640f28766b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ForeignPlanMember_019d0150-683a-7e06-9af6-603d9c8250d3" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ForeignPlanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanSponsorLocationDomain_019d0150-683a-7738-ab9c-7f9c2380ce6c" xlink:to="loc_us-gaap_ForeignPlanMember_019d0150-683a-7e06-9af6-603d9c8250d3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostAbstract_019d0150-683a-74a4-b9bf-961a470fac94" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_019d0150-683a-7ae3-b835-2b885b4e623c" xlink:to="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostAbstract_019d0150-683a-74a4-b9bf-961a470fac94" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanServiceCost_019d0150-683a-7ab4-baa8-712a7ff03c03" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanServiceCost"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostAbstract_019d0150-683a-74a4-b9bf-961a470fac94" xlink:to="loc_us-gaap_DefinedBenefitPlanServiceCost_019d0150-683a-7ab4-baa8-712a7ff03c03" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanInterestCost_019d0150-683a-7a63-b911-6748ee9925eb" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanInterestCost"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostAbstract_019d0150-683a-74a4-b9bf-961a470fac94" xlink:to="loc_us-gaap_DefinedBenefitPlanInterestCost_019d0150-683a-7a63-b911-6748ee9925eb" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets_019d0150-683a-7f6c-ad2c-ab587698bffd" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostAbstract_019d0150-683a-74a4-b9bf-961a470fac94" xlink:to="loc_us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets_019d0150-683a-7f6c-ad2c-ab587698bffd" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanAmortizationOfPriorServiceCostCredit_019d0150-683a-7661-b6b8-bd4866852b66" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanAmortizationOfPriorServiceCostCredit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostAbstract_019d0150-683a-74a4-b9bf-961a470fac94" xlink:to="loc_us-gaap_DefinedBenefitPlanAmortizationOfPriorServiceCostCredit_019d0150-683a-7661-b6b8-bd4866852b66" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost_019d0150-683a-7359-a931-34dff6ea5e84" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostAbstract_019d0150-683a-74a4-b9bf-961a470fac94" xlink:to="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost_019d0150-683a-7359-a931-34dff6ea5e84" xlink:type="arc" order="5"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.cat.com/role/PostretirementBenefitsDetails" xlink:type="simple" xlink:href="cat-20260331.xsd#PostretirementBenefitsDetails"/>
  <link:definitionLink xlink:role="http://www.cat.com/role/PostretirementBenefitsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_019d0150-683a-7d68-ba83-a80b533f8812" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanDisclosureLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_019d0150-683a-7f90-939d-1956399a6b01" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_019d0150-683a-7d68-ba83-a80b533f8812" xlink:to="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_019d0150-683a-7f90-939d-1956399a6b01" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeAxis_019d0150-683a-79a6-aa83-2d9921db287c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RetirementPlanTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_019d0150-683a-7f90-939d-1956399a6b01" xlink:to="loc_us-gaap_RetirementPlanTypeAxis_019d0150-683a-79a6-aa83-2d9921db287c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_019d0150-683a-79a6-aa83-2d9921db287c_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RetirementPlanTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_019d0150-683a-79a6-aa83-2d9921db287c" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_019d0150-683a-79a6-aa83-2d9921db287c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_019d0150-683a-70fe-b8ef-83e50920cc80" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RetirementPlanTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_019d0150-683a-79a6-aa83-2d9921db287c" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_019d0150-683a-70fe-b8ef-83e50920cc80" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PensionPlansDefinedBenefitMember_019d0150-683a-7c01-ba25-72f6655cebf2" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PensionPlansDefinedBenefitMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanTypeDomain_019d0150-683a-70fe-b8ef-83e50920cc80" xlink:to="loc_us-gaap_PensionPlansDefinedBenefitMember_019d0150-683a-7c01-ba25-72f6655cebf2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PensionAndOtherPostretirementBenefitContributions_019d0150-683a-7d23-8826-60b816d33f77" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PensionAndOtherPostretirementBenefitContributions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_019d0150-683a-7d68-ba83-a80b533f8812" xlink:to="loc_us-gaap_PensionAndOtherPostretirementBenefitContributions_019d0150-683a-7d23-8826-60b816d33f77" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanExpectedFutureEmployerContributionsCurrentFiscalYear_019d0150-683a-79d2-b957-a42e857b2bde" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanExpectedFutureEmployerContributionsCurrentFiscalYear"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_019d0150-683a-7d68-ba83-a80b533f8812" xlink:to="loc_us-gaap_DefinedBenefitPlanExpectedFutureEmployerContributionsCurrentFiscalYear_019d0150-683a-79d2-b957-a42e857b2bde" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.cat.com/role/PostretirementBenefitsSummaryOfCompanyCostsRelatedToUSAndNonUSDefinedContributionPlansDetails" xlink:type="simple" xlink:href="cat-20260331.xsd#PostretirementBenefitsSummaryOfCompanyCostsRelatedToUSAndNonUSDefinedContributionPlansDetails"/>
  <link:definitionLink xlink:role="http://www.cat.com/role/PostretirementBenefitsSummaryOfCompanyCostsRelatedToUSAndNonUSDefinedContributionPlansDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedContributionPlanDisclosureLineItems_019d0150-683a-71c3-9d5d-56a2e830145f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedContributionPlanDisclosureLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedContributionPlanTable_019d0150-683a-7000-b29d-79eba578d5ce" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedContributionPlanTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DefinedContributionPlanDisclosureLineItems_019d0150-683a-71c3-9d5d-56a2e830145f" xlink:to="loc_us-gaap_DefinedContributionPlanTable_019d0150-683a-7000-b29d-79eba578d5ce" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanSponsorLocationAxis_019d0150-683a-7f17-80fd-c54b820d924e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RetirementPlanSponsorLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DefinedContributionPlanTable_019d0150-683a-7000-b29d-79eba578d5ce" xlink:to="loc_us-gaap_RetirementPlanSponsorLocationAxis_019d0150-683a-7f17-80fd-c54b820d924e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanSponsorLocationDomain_019d0150-683a-7f17-80fd-c54b820d924e_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RetirementPlanSponsorLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RetirementPlanSponsorLocationAxis_019d0150-683a-7f17-80fd-c54b820d924e" xlink:to="loc_us-gaap_RetirementPlanSponsorLocationDomain_019d0150-683a-7f17-80fd-c54b820d924e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanSponsorLocationDomain_019d0150-683a-7ea4-84e3-bd106a76dbe5" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RetirementPlanSponsorLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RetirementPlanSponsorLocationAxis_019d0150-683a-7f17-80fd-c54b820d924e" xlink:to="loc_us-gaap_RetirementPlanSponsorLocationDomain_019d0150-683a-7ea4-84e3-bd106a76dbe5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DomesticPlanMember_019d0150-683a-72cc-8e5b-017efdfb6103" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DomesticPlanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanSponsorLocationDomain_019d0150-683a-7ea4-84e3-bd106a76dbe5" xlink:to="loc_us-gaap_DomesticPlanMember_019d0150-683a-72cc-8e5b-017efdfb6103" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_country_US_019d0150-683a-7cbc-8d05-9c0d555ae0be" xlink:href="https://xbrl.sec.gov/country/2025/country-2025.xsd#country_US"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DomesticPlanMember_019d0150-683a-72cc-8e5b-017efdfb6103" xlink:to="loc_country_US_019d0150-683a-7cbc-8d05-9c0d555ae0be" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ForeignPlanMember_019d0150-683a-7932-a2e9-3c5669ca0b28" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ForeignPlanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanSponsorLocationDomain_019d0150-683a-7ea4-84e3-bd106a76dbe5" xlink:to="loc_us-gaap_ForeignPlanMember_019d0150-683a-7932-a2e9-3c5669ca0b28" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedContributionPlanCostRecognized_019d0150-683a-75d6-9df9-01e77ee83b27" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedContributionPlanCostRecognized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedContributionPlanDisclosureLineItems_019d0150-683a-71c3-9d5d-56a2e830145f" xlink:to="loc_us-gaap_DefinedContributionPlanCostRecognized_019d0150-683a-75d6-9df9-01e77ee83b27" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.cat.com/role/GuaranteesandProductWarrantyDetails" xlink:type="simple" xlink:href="cat-20260331.xsd#GuaranteesandProductWarrantyDetails"/>
  <link:definitionLink xlink:role="http://www.cat.com/role/GuaranteesandProductWarrantyDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GuaranteeObligationsLineItems_019d0150-683a-74ed-8f03-8770df1bf8b0" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_GuaranteeObligationsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfGuaranteeObligationsTable_019d0150-683a-7cba-9af2-540836f36930" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfGuaranteeObligationsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_GuaranteeObligationsLineItems_019d0150-683a-74ed-8f03-8770df1bf8b0" xlink:to="loc_us-gaap_ScheduleOfGuaranteeObligationsTable_019d0150-683a-7cba-9af2-540836f36930" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesAxis_019d0150-683a-7953-bdae-1bea36c387e2" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_ConsolidatedEntitiesAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfGuaranteeObligationsTable_019d0150-683a-7cba-9af2-540836f36930" xlink:to="loc_srt_ConsolidatedEntitiesAxis_019d0150-683a-7953-bdae-1bea36c387e2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesDomain_019d0150-683a-7953-bdae-1bea36c387e2_default" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_ConsolidatedEntitiesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ConsolidatedEntitiesAxis_019d0150-683a-7953-bdae-1bea36c387e2" xlink:to="loc_srt_ConsolidatedEntitiesDomain_019d0150-683a-7953-bdae-1bea36c387e2_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesDomain_019d0150-683a-741f-b5b3-d93d68e99356" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_ConsolidatedEntitiesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ConsolidatedEntitiesAxis_019d0150-683a-7953-bdae-1bea36c387e2" xlink:to="loc_srt_ConsolidatedEntitiesDomain_019d0150-683a-741f-b5b3-d93d68e99356" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableInterestEntityPrimaryBeneficiaryMember_019d0150-683a-7ce5-8f2c-df51013c544b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_VariableInterestEntityPrimaryBeneficiaryMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidatedEntitiesDomain_019d0150-683a-741f-b5b3-d93d68e99356" xlink:to="loc_us-gaap_VariableInterestEntityPrimaryBeneficiaryMember_019d0150-683a-7ce5-8f2c-df51013c544b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GuaranteeObligationsMaximumExposure_019d0150-683a-7c7e-be15-ae52beff43cc" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_GuaranteeObligationsMaximumExposure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GuaranteeObligationsLineItems_019d0150-683a-74ed-8f03-8770df1bf8b0" xlink:to="loc_us-gaap_GuaranteeObligationsMaximumExposure_019d0150-683a-7c7e-be15-ae52beff43cc" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Assets_019d0150-683a-7922-b025-5c9dd10e00dc" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_Assets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GuaranteeObligationsLineItems_019d0150-683a-74ed-8f03-8770df1bf8b0" xlink:to="loc_us-gaap_Assets_019d0150-683a-7922-b025-5c9dd10e00dc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Liabilities_019d0150-683a-74d9-84da-3487cd6ad5c1" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_Liabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GuaranteeObligationsLineItems_019d0150-683a-74ed-8f03-8770df1bf8b0" xlink:to="loc_us-gaap_Liabilities_019d0150-683a-74d9-84da-3487cd6ad5c1" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.cat.com/role/ProfitPerShareDetails" xlink:type="simple" xlink:href="cat-20260331.xsd#ProfitPerShareDetails"/>
  <link:definitionLink xlink:role="http://www.cat.com/role/ProfitPerShareDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareBasicLineItems_019d0150-683a-7f24-b1fd-3281208baf56" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EarningsPerShareBasicLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfEarningsPerShareBasicByCommonClassTable_019d0150-683a-79bd-be29-6d1c69ce9ca8" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfEarningsPerShareBasicByCommonClassTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_EarningsPerShareBasicLineItems_019d0150-683a-7f24-b1fd-3281208baf56" xlink:to="loc_us-gaap_ScheduleOfEarningsPerShareBasicByCommonClassTable_019d0150-683a-79bd-be29-6d1c69ce9ca8" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ShareRepurchaseProgramAxis_019d0150-683a-79c2-a1b8-244fe1c42914" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_ShareRepurchaseProgramAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEarningsPerShareBasicByCommonClassTable_019d0150-683a-79bd-be29-6d1c69ce9ca8" xlink:to="loc_srt_ShareRepurchaseProgramAxis_019d0150-683a-79c2-a1b8-244fe1c42914" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ShareRepurchaseProgramDomain_019d0150-683a-79c2-a1b8-244fe1c42914_default" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_ShareRepurchaseProgramDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ShareRepurchaseProgramAxis_019d0150-683a-79c2-a1b8-244fe1c42914" xlink:to="loc_srt_ShareRepurchaseProgramDomain_019d0150-683a-79c2-a1b8-244fe1c42914_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ShareRepurchaseProgramDomain_019d0150-683a-74d3-a4d0-44b2b5711afd" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_ShareRepurchaseProgramDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ShareRepurchaseProgramAxis_019d0150-683a-79c2-a1b8-244fe1c42914" xlink:to="loc_srt_ShareRepurchaseProgramDomain_019d0150-683a-74d3-a4d0-44b2b5711afd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_ASRAgreementsMember_019d0150-683a-79d0-b79b-3e88fb73e093" xlink:href="cat-20260331.xsd#cat_ASRAgreementsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ShareRepurchaseProgramDomain_019d0150-683a-74d3-a4d0-44b2b5711afd" xlink:to="loc_cat_ASRAgreementsMember_019d0150-683a-79d0-b79b-3e88fb73e093" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_019d0150-683a-737f-8a80-a240a94db561" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareBasicLineItems_019d0150-683a-7f24-b1fd-3281208baf56" xlink:to="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_019d0150-683a-737f-8a80-a240a94db561" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TreasuryStockSharesAcquired_019d0150-683a-7c9f-aab8-ac0dc0b0e330" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_TreasuryStockSharesAcquired"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareBasicLineItems_019d0150-683a-7f24-b1fd-3281208baf56" xlink:to="loc_us-gaap_TreasuryStockSharesAcquired_019d0150-683a-7c9f-aab8-ac0dc0b0e330" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TreasuryStockValueAcquiredCostMethod_019d0150-683a-7c80-b8d2-72a4208aee7f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_TreasuryStockValueAcquiredCostMethod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareBasicLineItems_019d0150-683a-7f24-b1fd-3281208baf56" xlink:to="loc_us-gaap_TreasuryStockValueAcquiredCostMethod_019d0150-683a-7c80-b8d2-72a4208aee7f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsForRepurchaseOfCommonStock_019d0150-683a-7461-ab4b-aadad1461af5" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PaymentsForRepurchaseOfCommonStock"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareBasicLineItems_019d0150-683a-7f24-b1fd-3281208baf56" xlink:to="loc_us-gaap_PaymentsForRepurchaseOfCommonStock_019d0150-683a-7461-ab4b-aadad1461af5" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_RepurchaseOfCommonStockASRAgreementsPercentageOfInitialCommonShares_019d0150-683a-7681-8b78-e9b02e61e3a4" xlink:href="cat-20260331.xsd#cat_RepurchaseOfCommonStockASRAgreementsPercentageOfInitialCommonShares"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareBasicLineItems_019d0150-683a-7f24-b1fd-3281208baf56" xlink:to="loc_cat_RepurchaseOfCommonStockASRAgreementsPercentageOfInitialCommonShares_019d0150-683a-7681-8b78-e9b02e61e3a4" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_StockRepurchaseProgramAcceleratedShareRepurchasesUnsettledForwardContractIndexToCommonStock_019d0150-683a-7dae-9ca2-3f4d8ea6748f" xlink:href="cat-20260331.xsd#cat_StockRepurchaseProgramAcceleratedShareRepurchasesUnsettledForwardContractIndexToCommonStock"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareBasicLineItems_019d0150-683a-7f24-b1fd-3281208baf56" xlink:to="loc_cat_StockRepurchaseProgramAcceleratedShareRepurchasesUnsettledForwardContractIndexToCommonStock_019d0150-683a-7dae-9ca2-3f4d8ea6748f" xlink:type="arc" order="5"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.cat.com/role/AccumulatedOtherComprehensiveIncomeLossDetails" xlink:type="simple" xlink:href="cat-20260331.xsd#AccumulatedOtherComprehensiveIncomeLossDetails"/>
  <link:definitionLink xlink:role="http://www.cat.com/role/AccumulatedOtherComprehensiveIncomeLossDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_019d0150-683a-724e-a6d1-e255562838f6" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_019d0150-683a-77c3-9cc9-43606603c305" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_019d0150-683a-724e-a6d1-e255562838f6" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_019d0150-683a-77c3-9cc9-43606603c305" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_019d0150-683a-78c1-9504-db2befee6897" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_019d0150-683a-77c3-9cc9-43606603c305" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_019d0150-683a-78c1-9504-db2befee6897" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_019d0150-683a-78c1-9504-db2befee6897_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_019d0150-683a-78c1-9504-db2befee6897" xlink:to="loc_us-gaap_EquityComponentDomain_019d0150-683a-78c1-9504-db2befee6897_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_019d0150-683a-7116-9963-0675b1db0cf8" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_019d0150-683a-78c1-9504-db2befee6897" xlink:to="loc_us-gaap_EquityComponentDomain_019d0150-683a-7116-9963-0675b1db0cf8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedTranslationAdjustmentMember_019d0150-683a-7d32-becc-127731c13f3c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccumulatedTranslationAdjustmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_019d0150-683a-7116-9963-0675b1db0cf8" xlink:to="loc_us-gaap_AccumulatedTranslationAdjustmentMember_019d0150-683a-7d32-becc-127731c13f3c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember_019d0150-683a-7514-93f1-18cf011fa410" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_019d0150-683a-7116-9963-0675b1db0cf8" xlink:to="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember_019d0150-683a-7514-93f1-18cf011fa410" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedGainLossNetCashFlowHedgeParentMember_019d0150-683a-7a34-ac05-a1711262aeae" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccumulatedGainLossNetCashFlowHedgeParentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_019d0150-683a-7116-9963-0675b1db0cf8" xlink:to="loc_us-gaap_AccumulatedGainLossNetCashFlowHedgeParentMember_019d0150-683a-7a34-ac05-a1711262aeae" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedNetUnrealizedInvestmentGainLossMember_019d0150-683a-7486-a5a5-49fe10a96bb7" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccumulatedNetUnrealizedInvestmentGainLossMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_019d0150-683a-7116-9963-0675b1db0cf8" xlink:to="loc_us-gaap_AccumulatedNetUnrealizedInvestmentGainLossMember_019d0150-683a-7486-a5a5-49fe10a96bb7" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_019d0150-683a-77c7-97ef-af125cd185b9" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_019d0150-683a-7116-9963-0675b1db0cf8" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_019d0150-683a-77c7-97ef-af125cd185b9" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTaxAbstract_019d0150-683a-7ff9-827b-52b8719a4c0b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTaxAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_019d0150-683a-724e-a6d1-e255562838f6" xlink:to="loc_us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTaxAbstract_019d0150-683a-7ff9-827b-52b8719a4c0b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_019d0150-683a-735c-9e34-7e33fa7c041f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTaxAbstract_019d0150-683a-7ff9-827b-52b8719a4c0b" xlink:to="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_019d0150-683a-735c-9e34-7e33fa7c041f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsBeforeTax_019d0150-683a-71cb-863c-4a412e2ee931" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsBeforeTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTaxAbstract_019d0150-683a-7ff9-827b-52b8719a4c0b" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsBeforeTax_019d0150-683a-71cb-863c-4a412e2ee931" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsTax_019d0150-683a-706e-9e6f-f2a25e08cdee" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTaxAbstract_019d0150-683a-7ff9-827b-52b8719a4c0b" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsTax_019d0150-683a-706e-9e6f-f2a25e08cdee" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax_019d0150-683a-7abe-92f8-96d31ac04e5a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTaxAbstract_019d0150-683a-7ff9-827b-52b8719a4c0b" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax_019d0150-683a-7abe-92f8-96d31ac04e5a" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodBeforeTax_019d0150-683a-74c4-aa37-032ac0fad698" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodBeforeTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTaxAbstract_019d0150-683a-7ff9-827b-52b8719a4c0b" xlink:to="loc_us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodBeforeTax_019d0150-683a-74c4-aa37-032ac0fad698" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationFromAociCurrentPeriodTax_019d0150-683a-7dde-919f-e93d46a45eda" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ReclassificationFromAociCurrentPeriodTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTaxAbstract_019d0150-683a-7ff9-827b-52b8719a4c0b" xlink:to="loc_us-gaap_ReclassificationFromAociCurrentPeriodTax_019d0150-683a-7dde-919f-e93d46a45eda" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax_019d0150-683a-72d2-b585-f957b53438d0" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTaxAbstract_019d0150-683a-7ff9-827b-52b8719a4c0b" xlink:to="loc_us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax_019d0150-683a-72d2-b585-f957b53438d0" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_019d0150-683a-727a-a1e1-e8fa35e11572" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTaxAbstract_019d0150-683a-7ff9-827b-52b8719a4c0b" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_019d0150-683a-727a-a1e1-e8fa35e11572" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_019d0150-683a-7fa1-a47a-4250439f910e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.cat.com/role/SegmentInformationDetails" xlink:type="simple" xlink:href="cat-20260331.xsd#SegmentInformationDetails"/>
  <link:definitionLink xlink:role="http://www.cat.com/role/SegmentInformationDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentReportingInformationLineItems_019d0150-683a-7348-b9b0-cb53e6be4c77" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SegmentReportingInformationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_019d0150-683a-7923-bdb4-25608c72c743" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019d0150-683a-7348-b9b0-cb53e6be4c77" xlink:to="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_019d0150-683a-7923-bdb4-25608c72c743" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsegmentsConsolidationItemsAxis_019d0150-683a-7873-980c-5efbfd54205f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SubsegmentsConsolidationItemsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_019d0150-683a-7923-bdb4-25608c72c743" xlink:to="loc_us-gaap_SubsegmentsConsolidationItemsAxis_019d0150-683a-7873-980c-5efbfd54205f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsegmentsConsolidationItemsDomain_019d0150-683a-7873-980c-5efbfd54205f_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SubsegmentsConsolidationItemsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_SubsegmentsConsolidationItemsAxis_019d0150-683a-7873-980c-5efbfd54205f" xlink:to="loc_us-gaap_SubsegmentsConsolidationItemsDomain_019d0150-683a-7873-980c-5efbfd54205f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsegmentsConsolidationItemsDomain_019d0150-683a-7b6a-b16b-6e04e8f16f45" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SubsegmentsConsolidationItemsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_SubsegmentsConsolidationItemsAxis_019d0150-683a-7873-980c-5efbfd54205f" xlink:to="loc_us-gaap_SubsegmentsConsolidationItemsDomain_019d0150-683a-7b6a-b16b-6e04e8f16f45" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReportableSubsegmentsMember_019d0150-683a-7d1f-8c0c-e363de0a6257" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ReportableSubsegmentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsegmentsConsolidationItemsDomain_019d0150-683a-7b6a-b16b-6e04e8f16f45" xlink:to="loc_us-gaap_ReportableSubsegmentsMember_019d0150-683a-7d1f-8c0c-e363de0a6257" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_NonreportableSubsegmentsMember_019d0150-683a-7178-87df-51f2a897dea0" xlink:href="cat-20260331.xsd#cat_NonreportableSubsegmentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsegmentsConsolidationItemsDomain_019d0150-683a-7b6a-b16b-6e04e8f16f45" xlink:to="loc_cat_NonreportableSubsegmentsMember_019d0150-683a-7178-87df-51f2a897dea0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_NumberOfGroupPresidents_019d0150-683a-7733-bfec-45da6171bf2d" xlink:href="cat-20260331.xsd#cat_NumberOfGroupPresidents"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019d0150-683a-7348-b9b0-cb53e6be4c77" xlink:to="loc_cat_NumberOfGroupPresidents_019d0150-683a-7733-bfec-45da6171bf2d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_NumberOfOperatingSegmentsLedByGroupPresidents_019d0150-683a-748e-b84d-885a6b28e437" xlink:href="cat-20260331.xsd#cat_NumberOfOperatingSegmentsLedByGroupPresidents"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019d0150-683a-7348-b9b0-cb53e6be4c77" xlink:to="loc_cat_NumberOfOperatingSegmentsLedByGroupPresidents_019d0150-683a-748e-b84d-885a6b28e437" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_NumberOfOperatingSegmentsLedByGroupPresidentResponsibleForCorporateServices_019d0150-683a-764b-8337-38e62c2c6d1d" xlink:href="cat-20260331.xsd#cat_NumberOfOperatingSegmentsLedByGroupPresidentResponsibleForCorporateServices"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019d0150-683a-7348-b9b0-cb53e6be4c77" xlink:to="loc_cat_NumberOfOperatingSegmentsLedByGroupPresidentResponsibleForCorporateServices_019d0150-683a-764b-8337-38e62c2c6d1d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_NumberOfSmallerOperatingSegmentsLedByGroupPresident_019d0150-683a-7122-94c9-18c05dbd749f" xlink:href="cat-20260331.xsd#cat_NumberOfSmallerOperatingSegmentsLedByGroupPresident"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019d0150-683a-7348-b9b0-cb53e6be4c77" xlink:to="loc_cat_NumberOfSmallerOperatingSegmentsLedByGroupPresident_019d0150-683a-7122-94c9-18c05dbd749f" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NumberOfOperatingSegments_019d0150-683a-73a7-9749-9289eb1bf314" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NumberOfOperatingSegments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019d0150-683a-7348-b9b0-cb53e6be4c77" xlink:to="loc_us-gaap_NumberOfOperatingSegments_019d0150-683a-73a7-9749-9289eb1bf314" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NumberOfReportableSegments_019d0150-683a-7ac8-8512-05b575c01752" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NumberOfReportableSegments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019d0150-683a-7348-b9b0-cb53e6be4c77" xlink:to="loc_us-gaap_NumberOfReportableSegments_019d0150-683a-7ac8-8512-05b575c01752" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_UsefulLifeToAmortizeGoodwillToSegmentAssets_019d0150-683a-728a-a7c7-0b3030409df7" xlink:href="cat-20260331.xsd#cat_UsefulLifeToAmortizeGoodwillToSegmentAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019d0150-683a-7348-b9b0-cb53e6be4c77" xlink:to="loc_cat_UsefulLifeToAmortizeGoodwillToSegmentAssets_019d0150-683a-728a-a7c7-0b3030409df7" xlink:type="arc" order="6"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.cat.com/role/SegmentInformationRevenueByGeographicRegionDetails" xlink:type="simple" xlink:href="cat-20260331.xsd#SegmentInformationRevenueByGeographicRegionDetails"/>
  <link:definitionLink xlink:role="http://www.cat.com/role/SegmentInformationRevenueByGeographicRegionDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisaggregationOfRevenueLineItems_019d0150-683a-7999-9fbf-13ea6e176c67" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DisaggregationOfRevenueLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisaggregationOfRevenueTable_019d0150-683a-75da-891c-30a965468261" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DisaggregationOfRevenueTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_019d0150-683a-7999-9fbf-13ea6e176c67" xlink:to="loc_us-gaap_DisaggregationOfRevenueTable_019d0150-683a-75da-891c-30a965468261" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_019d0150-683a-7b6a-9f01-5f8dfc40d372" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_019d0150-683a-75da-891c-30a965468261" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_019d0150-683a-7b6a-9f01-5f8dfc40d372" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_019d0150-683a-7b6a-9f01-5f8dfc40d372_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_019d0150-683a-7b6a-9f01-5f8dfc40d372" xlink:to="loc_us-gaap_SegmentDomain_019d0150-683a-7b6a-9f01-5f8dfc40d372_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_019d0150-683a-7def-bbb1-23a718941fb0" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_019d0150-683a-7b6a-9f01-5f8dfc40d372" xlink:to="loc_us-gaap_SegmentDomain_019d0150-683a-7def-bbb1-23a718941fb0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReportableSegmentAggregationBeforeOtherOperatingSegmentMember_019d0150-683a-7ba7-8a19-d9706da7dcea" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ReportableSegmentAggregationBeforeOtherOperatingSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019d0150-683a-7def-bbb1-23a718941fb0" xlink:to="loc_us-gaap_ReportableSegmentAggregationBeforeOtherOperatingSegmentMember_019d0150-683a-7ba7-8a19-d9706da7dcea" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_PowerEnergyMember_019d0150-683a-77cc-8a68-3342335a26cf" xlink:href="cat-20260331.xsd#cat_PowerEnergyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReportableSegmentAggregationBeforeOtherOperatingSegmentMember_019d0150-683a-7ba7-8a19-d9706da7dcea" xlink:to="loc_cat_PowerEnergyMember_019d0150-683a-77cc-8a68-3342335a26cf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_ConstructionIndustriesMember_019d0150-683a-775a-aa8c-b31f756c7aab" xlink:href="cat-20260331.xsd#cat_ConstructionIndustriesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReportableSegmentAggregationBeforeOtherOperatingSegmentMember_019d0150-683a-7ba7-8a19-d9706da7dcea" xlink:to="loc_cat_ConstructionIndustriesMember_019d0150-683a-775a-aa8c-b31f756c7aab" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_ResourceIndustriesMember_019d0150-683a-78a4-ae42-93cbb585935f" xlink:href="cat-20260331.xsd#cat_ResourceIndustriesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReportableSegmentAggregationBeforeOtherOperatingSegmentMember_019d0150-683a-7ba7-8a19-d9706da7dcea" xlink:to="loc_cat_ResourceIndustriesMember_019d0150-683a-78a4-ae42-93cbb585935f" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_FinancialProductsSegmentMember_019d0150-683a-7f20-9b34-a5a401ff0b66" xlink:href="cat-20260331.xsd#cat_FinancialProductsSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReportableSegmentAggregationBeforeOtherOperatingSegmentMember_019d0150-683a-7ba7-8a19-d9706da7dcea" xlink:to="loc_cat_FinancialProductsSegmentMember_019d0150-683a-7f20-9b34-a5a401ff0b66" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllOtherSegmentsMember_019d0150-683a-7104-85be-70e03fdd73a8" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AllOtherSegmentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019d0150-683a-7def-bbb1-23a718941fb0" xlink:to="loc_us-gaap_AllOtherSegmentsMember_019d0150-683a-7104-85be-70e03fdd73a8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_StatementGeographicalAxis_019d0150-683a-7532-9e0c-e2ee746c3f13" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_StatementGeographicalAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_019d0150-683a-75da-891c-30a965468261" xlink:to="loc_srt_StatementGeographicalAxis_019d0150-683a-7532-9e0c-e2ee746c3f13" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain_019d0150-683a-7532-9e0c-e2ee746c3f13_default" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_SegmentGeographicalDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_StatementGeographicalAxis_019d0150-683a-7532-9e0c-e2ee746c3f13" xlink:to="loc_srt_SegmentGeographicalDomain_019d0150-683a-7532-9e0c-e2ee746c3f13_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain_019d0150-683a-7f0a-b408-671d045adabd" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_SegmentGeographicalDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_StatementGeographicalAxis_019d0150-683a-7532-9e0c-e2ee746c3f13" xlink:to="loc_srt_SegmentGeographicalDomain_019d0150-683a-7f0a-b408-671d045adabd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_NorthAmericaMember_019d0150-683a-746f-a6b6-398b4d9b745f" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_NorthAmericaMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_019d0150-683a-7f0a-b408-671d045adabd" xlink:to="loc_srt_NorthAmericaMember_019d0150-683a-746f-a6b6-398b4d9b745f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_LatinAmericaMember_019d0150-683a-79c6-8493-e88b8023edb0" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_LatinAmericaMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_019d0150-683a-7f0a-b408-671d045adabd" xlink:to="loc_srt_LatinAmericaMember_019d0150-683a-79c6-8493-e88b8023edb0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EMEAMember_019d0150-683a-7200-8dfc-3471d595a127" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EMEAMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_019d0150-683a-7f0a-b408-671d045adabd" xlink:to="loc_us-gaap_EMEAMember_019d0150-683a-7200-8dfc-3471d595a127" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_AsiaPacificMember_019d0150-683a-7f8f-9d43-9290ac15bf2b" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_AsiaPacificMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_019d0150-683a-7f0a-b408-671d045adabd" xlink:to="loc_srt_AsiaPacificMember_019d0150-683a-7f8f-9d43-9290ac15bf2b" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsAxis_019d0150-683a-7a85-ae60-ebccc4df86f3" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_ConsolidationItemsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_019d0150-683a-75da-891c-30a965468261" xlink:to="loc_srt_ConsolidationItemsAxis_019d0150-683a-7a85-ae60-ebccc4df86f3" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_019d0150-683a-7a85-ae60-ebccc4df86f3_default" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_ConsolidationItemsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ConsolidationItemsAxis_019d0150-683a-7a85-ae60-ebccc4df86f3" xlink:to="loc_srt_ConsolidationItemsDomain_019d0150-683a-7a85-ae60-ebccc4df86f3_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_019d0150-683a-71f4-8fb7-dedcead5d90b" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_ConsolidationItemsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ConsolidationItemsAxis_019d0150-683a-7a85-ae60-ebccc4df86f3" xlink:to="loc_srt_ConsolidationItemsDomain_019d0150-683a-71f4-8fb7-dedcead5d90b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_OperatingSegmentsExcludingIntersegmentEliminationMember_019d0150-683a-7c4b-8e07-26d4b0ec406c" xlink:href="cat-20260331.xsd#cat_OperatingSegmentsExcludingIntersegmentEliminationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidationItemsDomain_019d0150-683a-71f4-8fb7-dedcead5d90b" xlink:to="loc_cat_OperatingSegmentsExcludingIntersegmentEliminationMember_019d0150-683a-7c4b-8e07-26d4b0ec406c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IntersegmentEliminationMember_019d0150-683a-7ff0-b218-acba68b3d3d9" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IntersegmentEliminationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidationItemsDomain_019d0150-683a-71f4-8fb7-dedcead5d90b" xlink:to="loc_us-gaap_IntersegmentEliminationMember_019d0150-683a-7ff0-b218-acba68b3d3d9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingSegmentsMember_019d0150-683a-778d-8981-a9b60e357626" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OperatingSegmentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidationItemsDomain_019d0150-683a-71f4-8fb7-dedcead5d90b" xlink:to="loc_us-gaap_OperatingSegmentsMember_019d0150-683a-778d-8981-a9b60e357626" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CorporateNonSegmentMember_019d0150-683a-70c2-aec5-74fa633bf95d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CorporateNonSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidationItemsDomain_019d0150-683a-71f4-8fb7-dedcead5d90b" xlink:to="loc_us-gaap_CorporateNonSegmentMember_019d0150-683a-70c2-aec5-74fa633bf95d" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_EliminationsAndReconcilingItemsMember_019d0150-683a-77c9-9ca4-6130cc85e7c1" xlink:href="cat-20260331.xsd#cat_EliminationsAndReconcilingItemsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidationItemsDomain_019d0150-683a-71f4-8fb7-dedcead5d90b" xlink:to="loc_cat_EliminationsAndReconcilingItemsMember_019d0150-683a-77c9-9ca4-6130cc85e7c1" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019d0150-683a-78c3-b721-d0ded31d2701" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_019d0150-683a-75da-891c-30a965468261" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019d0150-683a-78c3-b721-d0ded31d2701" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_019d0150-683a-78c3-b721-d0ded31d2701_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019d0150-683a-78c3-b721-d0ded31d2701" xlink:to="loc_us-gaap_RelatedPartyDomain_019d0150-683a-78c3-b721-d0ded31d2701_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_019d0150-683a-7d19-a477-ee567efd9b12" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019d0150-683a-78c3-b721-d0ded31d2701" xlink:to="loc_us-gaap_RelatedPartyDomain_019d0150-683a-7d19-a477-ee567efd9b12" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyMember_019d0150-683a-7aa9-832e-20c8b862feb6" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RelatedPartyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_019d0150-683a-7d19-a477-ee567efd9b12" xlink:to="loc_us-gaap_RelatedPartyMember_019d0150-683a-7aa9-832e-20c8b862feb6" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Revenues_019d0150-683a-7d8c-9259-13ae91697fe2" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_Revenues"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_019d0150-683a-7999-9fbf-13ea6e176c67" xlink:to="loc_us-gaap_Revenues_019d0150-683a-7d8c-9259-13ae91697fe2" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.cat.com/role/SegmentInformationExternalSalesByEndUserApplicationDetails" xlink:type="simple" xlink:href="cat-20260331.xsd#SegmentInformationExternalSalesByEndUserApplicationDetails"/>
  <link:definitionLink xlink:role="http://www.cat.com/role/SegmentInformationExternalSalesByEndUserApplicationDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisaggregationOfRevenueLineItems_019d0150-683a-7a54-afe3-c58ff05796ab" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DisaggregationOfRevenueLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisaggregationOfRevenueTable_019d0150-683a-7a96-8eea-1b1667f4ce92" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DisaggregationOfRevenueTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_019d0150-683a-7a54-afe3-c58ff05796ab" xlink:to="loc_us-gaap_DisaggregationOfRevenueTable_019d0150-683a-7a96-8eea-1b1667f4ce92" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_019d0150-683a-7b57-a679-ee7798b8ce31" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_019d0150-683a-7a96-8eea-1b1667f4ce92" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_019d0150-683a-7b57-a679-ee7798b8ce31" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_019d0150-683a-7b57-a679-ee7798b8ce31_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_019d0150-683a-7b57-a679-ee7798b8ce31" xlink:to="loc_us-gaap_SegmentDomain_019d0150-683a-7b57-a679-ee7798b8ce31_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_019d0150-683a-79de-8a49-743401f8ccb2" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_019d0150-683a-7b57-a679-ee7798b8ce31" xlink:to="loc_us-gaap_SegmentDomain_019d0150-683a-79de-8a49-743401f8ccb2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_PowerEnergyMember_019d0150-683a-72eb-94dc-dc52c75862d3" xlink:href="cat-20260331.xsd#cat_PowerEnergyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019d0150-683a-79de-8a49-743401f8ccb2" xlink:to="loc_cat_PowerEnergyMember_019d0150-683a-72eb-94dc-dc52c75862d3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_ResourceIndustriesMember_019dbb44-36e5-7639-8f2b-53265fa731af" xlink:href="cat-20260331.xsd#cat_ResourceIndustriesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019d0150-683a-79de-8a49-743401f8ccb2" xlink:to="loc_cat_ResourceIndustriesMember_019dbb44-36e5-7639-8f2b-53265fa731af" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MajorCustomersAxis_019d0150-683a-7b7d-8c50-c31f0fe89374" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_MajorCustomersAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_019d0150-683a-7a96-8eea-1b1667f4ce92" xlink:to="loc_srt_MajorCustomersAxis_019d0150-683a-7b7d-8c50-c31f0fe89374" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_NameOfMajorCustomerDomain_019d0150-683a-7b7d-8c50-c31f0fe89374_default" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_NameOfMajorCustomerDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_MajorCustomersAxis_019d0150-683a-7b7d-8c50-c31f0fe89374" xlink:to="loc_srt_NameOfMajorCustomerDomain_019d0150-683a-7b7d-8c50-c31f0fe89374_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_NameOfMajorCustomerDomain_019d0150-683a-7298-b74a-1b595589e318" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_NameOfMajorCustomerDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_MajorCustomersAxis_019d0150-683a-7b7d-8c50-c31f0fe89374" xlink:to="loc_srt_NameOfMajorCustomerDomain_019d0150-683a-7298-b74a-1b595589e318" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_PowergenerationMember_019d0150-683a-7bed-845a-e395456b0574" xlink:href="cat-20260331.xsd#cat_PowergenerationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_NameOfMajorCustomerDomain_019d0150-683a-7298-b74a-1b595589e318" xlink:to="loc_cat_PowergenerationMember_019d0150-683a-7bed-845a-e395456b0574" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_OilAndGasCustomerMember_019d0150-683a-79f4-94dd-30fd3eee9d58" xlink:href="cat-20260331.xsd#cat_OilAndGasCustomerMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_NameOfMajorCustomerDomain_019d0150-683a-7298-b74a-1b595589e318" xlink:to="loc_cat_OilAndGasCustomerMember_019d0150-683a-79f4-94dd-30fd3eee9d58" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_IndustrialMember_019d0150-683a-719a-8b6c-4f1f9fe058d5" xlink:href="cat-20260331.xsd#cat_IndustrialMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_NameOfMajorCustomerDomain_019d0150-683a-7298-b74a-1b595589e318" xlink:to="loc_cat_IndustrialMember_019d0150-683a-719a-8b6c-4f1f9fe058d5" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_MiningHeavyConstructionAndQuarryAggregatesMember_019dbb44-36e5-7f2b-8ca5-bb88a0abc991" xlink:href="cat-20260331.xsd#cat_MiningHeavyConstructionAndQuarryAggregatesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_NameOfMajorCustomerDomain_019d0150-683a-7298-b74a-1b595589e318" xlink:to="loc_cat_MiningHeavyConstructionAndQuarryAggregatesMember_019dbb44-36e5-7f2b-8ca5-bb88a0abc991" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_RailMember_019dbb44-36e5-758d-85ac-74a03942c10f" xlink:href="cat-20260331.xsd#cat_RailMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_NameOfMajorCustomerDomain_019d0150-683a-7298-b74a-1b595589e318" xlink:to="loc_cat_RailMember_019dbb44-36e5-758d-85ac-74a03942c10f" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Revenues_019d0150-683a-7f4a-a4b8-8e6270c758ed" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_Revenues"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_019d0150-683a-7a54-afe3-c58ff05796ab" xlink:to="loc_us-gaap_Revenues_019d0150-683a-7f4a-a4b8-8e6270c758ed" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.cat.com/role/SegmentinformationReconciliationofProfitfromReportableSegmentsDetails" xlink:type="simple" xlink:href="cat-20260331.xsd#SegmentinformationReconciliationofProfitfromReportableSegmentsDetails"/>
  <link:definitionLink xlink:role="http://www.cat.com/role/SegmentinformationReconciliationofProfitfromReportableSegmentsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentReportingInformationLineItems_019d0150-683a-7d29-b6a1-b4a172049d66" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SegmentReportingInformationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_019d0150-683a-7090-8d6e-a267f8c52bf3" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019d0150-683a-7d29-b6a1-b4a172049d66" xlink:to="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_019d0150-683a-7090-8d6e-a267f8c52bf3" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_019d0150-683a-7975-af10-a70d812f5f60" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_019d0150-683a-7090-8d6e-a267f8c52bf3" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_019d0150-683a-7975-af10-a70d812f5f60" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_019d0150-683a-7975-af10-a70d812f5f60_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_019d0150-683a-7975-af10-a70d812f5f60" xlink:to="loc_us-gaap_SegmentDomain_019d0150-683a-7975-af10-a70d812f5f60_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_019d0150-683a-7d94-9fa8-28fcfac38a18" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_019d0150-683a-7975-af10-a70d812f5f60" xlink:to="loc_us-gaap_SegmentDomain_019d0150-683a-7d94-9fa8-28fcfac38a18" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReportableSegmentAggregationBeforeOtherOperatingSegmentMember_019d0150-683a-7cd0-8c80-762829ca946e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ReportableSegmentAggregationBeforeOtherOperatingSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019d0150-683a-7d94-9fa8-28fcfac38a18" xlink:to="loc_us-gaap_ReportableSegmentAggregationBeforeOtherOperatingSegmentMember_019d0150-683a-7cd0-8c80-762829ca946e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_PowerEnergyMember_019d0150-683a-7a10-93da-ca1221c924ec" xlink:href="cat-20260331.xsd#cat_PowerEnergyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReportableSegmentAggregationBeforeOtherOperatingSegmentMember_019d0150-683a-7cd0-8c80-762829ca946e" xlink:to="loc_cat_PowerEnergyMember_019d0150-683a-7a10-93da-ca1221c924ec" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_ConstructionIndustriesMember_019d0150-683a-79fd-8106-bffae93ba999" xlink:href="cat-20260331.xsd#cat_ConstructionIndustriesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReportableSegmentAggregationBeforeOtherOperatingSegmentMember_019d0150-683a-7cd0-8c80-762829ca946e" xlink:to="loc_cat_ConstructionIndustriesMember_019d0150-683a-79fd-8106-bffae93ba999" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_ResourceIndustriesMember_019d0150-683a-7d53-bce2-c26585a81d4a" xlink:href="cat-20260331.xsd#cat_ResourceIndustriesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReportableSegmentAggregationBeforeOtherOperatingSegmentMember_019d0150-683a-7cd0-8c80-762829ca946e" xlink:to="loc_cat_ResourceIndustriesMember_019d0150-683a-7d53-bce2-c26585a81d4a" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_FinancialProductsSegmentMember_019d0150-683a-7954-8f1b-d1c44129ed66" xlink:href="cat-20260331.xsd#cat_FinancialProductsSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReportableSegmentAggregationBeforeOtherOperatingSegmentMember_019d0150-683a-7cd0-8c80-762829ca946e" xlink:to="loc_cat_FinancialProductsSegmentMember_019d0150-683a-7954-8f1b-d1c44129ed66" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsAxis_019d0150-683a-7494-882a-775fb438ba94" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_ConsolidationItemsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_019d0150-683a-7090-8d6e-a267f8c52bf3" xlink:to="loc_srt_ConsolidationItemsAxis_019d0150-683a-7494-882a-775fb438ba94" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_019d0150-683a-7494-882a-775fb438ba94_default" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_ConsolidationItemsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ConsolidationItemsAxis_019d0150-683a-7494-882a-775fb438ba94" xlink:to="loc_srt_ConsolidationItemsDomain_019d0150-683a-7494-882a-775fb438ba94_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_019d0150-683a-71ab-8d84-a14e16dd3445" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_ConsolidationItemsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ConsolidationItemsAxis_019d0150-683a-7494-882a-775fb438ba94" xlink:to="loc_srt_ConsolidationItemsDomain_019d0150-683a-71ab-8d84-a14e16dd3445" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingSegmentsMember_019d0150-683a-7e84-8bfc-84d15adc7ac4" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OperatingSegmentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidationItemsDomain_019d0150-683a-71ab-8d84-a14e16dd3445" xlink:to="loc_us-gaap_OperatingSegmentsMember_019d0150-683a-7e84-8bfc-84d15adc7ac4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Revenues_019d0150-683a-7a5e-8cc9-6bdc9eca8130" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_Revenues"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019d0150-683a-7d29-b6a1-b4a172049d66" xlink:to="loc_us-gaap_Revenues_019d0150-683a-7a5e-8cc9-6bdc9eca8130" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialServicesCostsAbstract_019d0150-683a-7aed-9b39-9e57386dbc8f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancialServicesCostsAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019d0150-683a-7d29-b6a1-b4a172049d66" xlink:to="loc_us-gaap_FinancialServicesCostsAbstract_019d0150-683a-7aed-9b39-9e57386dbc8f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CostOfRevenue_019d0150-683a-71aa-8964-cb9358a15f5d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CostOfRevenue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancialServicesCostsAbstract_019d0150-683a-7aed-9b39-9e57386dbc8f" xlink:to="loc_us-gaap_CostOfRevenue_019d0150-683a-71aa-8964-cb9358a15f5d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_SellingGeneralAndAdministrativeResearchAndDevelopment_019d0150-683a-70da-916f-451bd79c8928" xlink:href="cat-20260331.xsd#cat_SellingGeneralAndAdministrativeResearchAndDevelopment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancialServicesCostsAbstract_019d0150-683a-7aed-9b39-9e57386dbc8f" xlink:to="loc_cat_SellingGeneralAndAdministrativeResearchAndDevelopment_019d0150-683a-70da-916f-451bd79c8928" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentReportingOtherItemAmount_019d0150-683a-7e49-b388-7f5bd41b3c6f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SegmentReportingOtherItemAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancialServicesCostsAbstract_019d0150-683a-7aed-9b39-9e57386dbc8f" xlink:to="loc_us-gaap_SegmentReportingOtherItemAmount_019d0150-683a-7e49-b388-7f5bd41b3c6f" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments_019d0150-683a-7b45-92e0-2271cf7b3f23" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019d0150-683a-7d29-b6a1-b4a172049d66" xlink:to="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments_019d0150-683a-7b45-92e0-2271cf7b3f23" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.cat.com/role/SegmentinformationReconciliationsofConsolidatedProfitBeforeTaxesDetails" xlink:type="simple" xlink:href="cat-20260331.xsd#SegmentinformationReconciliationsofConsolidatedProfitBeforeTaxesDetails"/>
  <link:definitionLink xlink:role="http://www.cat.com/role/SegmentinformationReconciliationsofConsolidatedProfitBeforeTaxesDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisaggregationOfRevenueLineItems_019d0150-683a-7d3a-bb31-d45bbd0a9299" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DisaggregationOfRevenueLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisaggregationOfRevenueTable_019d0150-683a-7e8a-8516-72b68e4fa949" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DisaggregationOfRevenueTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_019d0150-683a-7d3a-bb31-d45bbd0a9299" xlink:to="loc_us-gaap_DisaggregationOfRevenueTable_019d0150-683a-7e8a-8516-72b68e4fa949" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_019d0150-683a-7bfb-9adc-ad466884cc99" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_019d0150-683a-7e8a-8516-72b68e4fa949" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_019d0150-683a-7bfb-9adc-ad466884cc99" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_019d0150-683a-7bfb-9adc-ad466884cc99_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_019d0150-683a-7bfb-9adc-ad466884cc99" xlink:to="loc_us-gaap_SegmentDomain_019d0150-683a-7bfb-9adc-ad466884cc99_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_019d0150-683a-7a98-bdb4-b9d95eaa8765" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_019d0150-683a-7bfb-9adc-ad466884cc99" xlink:to="loc_us-gaap_SegmentDomain_019d0150-683a-7a98-bdb4-b9d95eaa8765" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReportableSegmentAggregationBeforeOtherOperatingSegmentMember_019d0150-683a-7783-bbfc-20155964c655" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ReportableSegmentAggregationBeforeOtherOperatingSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019d0150-683a-7a98-bdb4-b9d95eaa8765" xlink:to="loc_us-gaap_ReportableSegmentAggregationBeforeOtherOperatingSegmentMember_019d0150-683a-7783-bbfc-20155964c655" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllOtherSegmentsMember_019d0150-683a-7607-83f5-f6e7b8e4ba2f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AllOtherSegmentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019d0150-683a-7a98-bdb4-b9d95eaa8765" xlink:to="loc_us-gaap_AllOtherSegmentsMember_019d0150-683a-7607-83f5-f6e7b8e4ba2f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments_019d0150-683a-7ca6-95a7-e2469a6c8de4" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_019d0150-683a-7d3a-bb31-d45bbd0a9299" xlink:to="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments_019d0150-683a-7ca6-95a7-e2469a6c8de4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_GainLossOnCostCenters_019d0150-683a-7f1b-b51d-d8d866e79d2c" xlink:href="cat-20260331.xsd#cat_GainLossOnCostCenters"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_019d0150-683a-7d3a-bb31-d45bbd0a9299" xlink:to="loc_cat_GainLossOnCostCenters_019d0150-683a-7f1b-b51d-d8d866e79d2c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_CorporateCosts_019d0150-683a-7534-8947-862dad468f40" xlink:href="cat-20260331.xsd#cat_CorporateCosts"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_019d0150-683a-7d3a-bb31-d45bbd0a9299" xlink:to="loc_cat_CorporateCosts_019d0150-683a-7534-8947-862dad468f40" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_GainLossOnTiming_019d0150-683a-7636-94d1-542f6b075483" xlink:href="cat-20260331.xsd#cat_GainLossOnTiming"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_019d0150-683a-7d3a-bb31-d45bbd0a9299" xlink:to="loc_cat_GainLossOnTiming_019d0150-683a-7636-94d1-542f6b075483" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringCosts_019d0150-683a-7463-accd-03c3cc012ee2" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RestructuringCosts"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_019d0150-683a-7d3a-bb31-d45bbd0a9299" xlink:to="loc_us-gaap_RestructuringCosts_019d0150-683a-7463-accd-03c3cc012ee2" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentReportingInformationRevenueAbstract_019d0150-683a-78ee-bff5-6b2866c2f16b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SegmentReportingInformationRevenueAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_019d0150-683a-7d3a-bb31-d45bbd0a9299" xlink:to="loc_us-gaap_SegmentReportingInformationRevenueAbstract_019d0150-683a-78ee-bff5-6b2866c2f16b" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_InventoryAndCostOfSales_019d0150-683a-712e-9762-7bd3294269ac" xlink:href="cat-20260331.xsd#cat_InventoryAndCostOfSales"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationRevenueAbstract_019d0150-683a-78ee-bff5-6b2866c2f16b" xlink:to="loc_cat_InventoryAndCostOfSales_019d0150-683a-712e-9762-7bd3294269ac" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost_019d0150-683a-73ce-8e03-f7a4d6e93b45" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationRevenueAbstract_019d0150-683a-78ee-bff5-6b2866c2f16b" xlink:to="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost_019d0150-683a-73ce-8e03-f7a4d6e93b45" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_ShareBasedPaymentArrangementNoncashExpenseAdjusted_019d0150-683a-75fb-9922-b515ab756c6b" xlink:href="cat-20260331.xsd#cat_ShareBasedPaymentArrangementNoncashExpenseAdjusted"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationRevenueAbstract_019d0150-683a-78ee-bff5-6b2866c2f16b" xlink:to="loc_cat_ShareBasedPaymentArrangementNoncashExpenseAdjusted_019d0150-683a-75fb-9922-b515ab756c6b" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_FinancingCosts_019d0150-683a-76c2-a212-5b30211db021" xlink:href="cat-20260331.xsd#cat_FinancingCosts"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationRevenueAbstract_019d0150-683a-78ee-bff5-6b2866c2f16b" xlink:to="loc_cat_FinancingCosts_019d0150-683a-76c2-a212-5b30211db021" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_CurrencyGainLoss_019d0150-683a-79ce-9d0b-b3523e94439c" xlink:href="cat-20260331.xsd#cat_CurrencyGainLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationRevenueAbstract_019d0150-683a-78ee-bff5-6b2866c2f16b" xlink:to="loc_cat_CurrencyGainLoss_019d0150-683a-79ce-9d0b-b3523e94439c" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_OtherNonoperatingIncomeExpenseAdjusted_019d0150-683a-7428-9467-93eadb49b5b0" xlink:href="cat-20260331.xsd#cat_OtherNonoperatingIncomeExpenseAdjusted"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationRevenueAbstract_019d0150-683a-78ee-bff5-6b2866c2f16b" xlink:to="loc_cat_OtherNonoperatingIncomeExpenseAdjusted_019d0150-683a-7428-9467-93eadb49b5b0" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_GainLossOtherMethodologyDifferences_019d0150-683a-79d3-b558-d35f5e7f28a7" xlink:href="cat-20260331.xsd#cat_GainLossOtherMethodologyDifferences"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationRevenueAbstract_019d0150-683a-78ee-bff5-6b2866c2f16b" xlink:to="loc_cat_GainLossOtherMethodologyDifferences_019d0150-683a-79d3-b558-d35f5e7f28a7" xlink:type="arc" order="7"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.cat.com/role/SegmentinformationReconciliationofAssetsDetails" xlink:type="simple" xlink:href="cat-20260331.xsd#SegmentinformationReconciliationofAssetsDetails"/>
  <link:definitionLink xlink:role="http://www.cat.com/role/SegmentinformationReconciliationofAssetsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentReportingAssetReconcilingItemLineItems_019d0150-683b-7291-a104-048dab0635ff" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SegmentReportingAssetReconcilingItemLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReconciliationOfAssetsFromSegmentToConsolidatedTable_019d0150-683a-7613-b4fd-02c97da55890" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ReconciliationOfAssetsFromSegmentToConsolidatedTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SegmentReportingAssetReconcilingItemLineItems_019d0150-683b-7291-a104-048dab0635ff" xlink:to="loc_us-gaap_ReconciliationOfAssetsFromSegmentToConsolidatedTable_019d0150-683a-7613-b4fd-02c97da55890" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsAxis_019d0150-683a-7071-a1ae-42a90a00bd1d" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_ConsolidationItemsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ReconciliationOfAssetsFromSegmentToConsolidatedTable_019d0150-683a-7613-b4fd-02c97da55890" xlink:to="loc_srt_ConsolidationItemsAxis_019d0150-683a-7071-a1ae-42a90a00bd1d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_019d0150-683a-7071-a1ae-42a90a00bd1d_default" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_ConsolidationItemsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ConsolidationItemsAxis_019d0150-683a-7071-a1ae-42a90a00bd1d" xlink:to="loc_srt_ConsolidationItemsDomain_019d0150-683a-7071-a1ae-42a90a00bd1d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_019d0150-683a-7d76-9e44-2e23be695d21" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_ConsolidationItemsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ConsolidationItemsAxis_019d0150-683a-7071-a1ae-42a90a00bd1d" xlink:to="loc_srt_ConsolidationItemsDomain_019d0150-683a-7d76-9e44-2e23be695d21" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingSegmentsMember_019d0150-683b-74ac-b8f0-df04bc3e8858" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OperatingSegmentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidationItemsDomain_019d0150-683a-7d76-9e44-2e23be695d21" xlink:to="loc_us-gaap_OperatingSegmentsMember_019d0150-683b-74ac-b8f0-df04bc3e8858" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CorporateNonSegmentMember_019d0150-683b-7895-91e1-e4ef26c2d9b1" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CorporateNonSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidationItemsDomain_019d0150-683a-7d76-9e44-2e23be695d21" xlink:to="loc_us-gaap_CorporateNonSegmentMember_019d0150-683b-7895-91e1-e4ef26c2d9b1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_019d0150-683b-70b4-b028-308f1e5554f1" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ReconciliationOfAssetsFromSegmentToConsolidatedTable_019d0150-683a-7613-b4fd-02c97da55890" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_019d0150-683b-70b4-b028-308f1e5554f1" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_019d0150-683b-70b4-b028-308f1e5554f1_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_019d0150-683b-70b4-b028-308f1e5554f1" xlink:to="loc_us-gaap_SegmentDomain_019d0150-683b-70b4-b028-308f1e5554f1_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_019d0150-683b-74e3-b707-754744791e0f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_019d0150-683b-70b4-b028-308f1e5554f1" xlink:to="loc_us-gaap_SegmentDomain_019d0150-683b-74e3-b707-754744791e0f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_PowerEnergyMember_019d0150-683b-7266-bc80-b2c05ac14025" xlink:href="cat-20260331.xsd#cat_PowerEnergyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019d0150-683b-74e3-b707-754744791e0f" xlink:to="loc_cat_PowerEnergyMember_019d0150-683b-7266-bc80-b2c05ac14025" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_ConstructionIndustriesMember_019d0150-683b-71d1-90ef-23c1dc156afc" xlink:href="cat-20260331.xsd#cat_ConstructionIndustriesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019d0150-683b-74e3-b707-754744791e0f" xlink:to="loc_cat_ConstructionIndustriesMember_019d0150-683b-71d1-90ef-23c1dc156afc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_ResourceIndustriesMember_019d0150-683b-77bf-a59b-9bd747915270" xlink:href="cat-20260331.xsd#cat_ResourceIndustriesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019d0150-683b-74e3-b707-754744791e0f" xlink:to="loc_cat_ResourceIndustriesMember_019d0150-683b-77bf-a59b-9bd747915270" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_FinancialProductsSegmentMember_019d0150-683b-7f62-99c6-26e53a4ac09f" xlink:href="cat-20260331.xsd#cat_FinancialProductsSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019d0150-683b-74e3-b707-754744791e0f" xlink:to="loc_cat_FinancialProductsSegmentMember_019d0150-683b-7f62-99c6-26e53a4ac09f" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllOtherSegmentsMember_019d0150-683b-7db2-b4cc-2a347498ca63" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AllOtherSegmentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019d0150-683b-74e3-b707-754744791e0f" xlink:to="loc_us-gaap_AllOtherSegmentsMember_019d0150-683b-7db2-b4cc-2a347498ca63" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Assets_019d0150-683b-7f97-a189-7a810af49f6d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_Assets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingAssetReconcilingItemLineItems_019d0150-683b-7291-a104-048dab0635ff" xlink:to="loc_us-gaap_Assets_019d0150-683b-7f97-a189-7a810af49f6d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentReportingInformationAdditionalInformationAbstract_019d0150-683b-784c-8928-f05e5629b8af" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SegmentReportingInformationAdditionalInformationAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingAssetReconcilingItemLineItems_019d0150-683b-7291-a104-048dab0635ff" xlink:to="loc_us-gaap_SegmentReportingInformationAdditionalInformationAbstract_019d0150-683b-784c-8928-f05e5629b8af" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_019d0150-683b-7c63-8844-715838926199" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationAdditionalInformationAbstract_019d0150-683b-784c-8928-f05e5629b8af" xlink:to="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_019d0150-683b-7c63-8844-715838926199" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredTaxAssetsLiabilitiesNet_019d0150-683b-7309-86df-3cd2d03ebf41" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DeferredTaxAssetsLiabilitiesNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationAdditionalInformationAbstract_019d0150-683b-784c-8928-f05e5629b8af" xlink:to="loc_us-gaap_DeferredTaxAssetsLiabilitiesNet_019d0150-683b-7309-86df-3cd2d03ebf41" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_GoodwillAndIntangibleAssets_019d0150-683b-7140-87c9-86e79786ec50" xlink:href="cat-20260331.xsd#cat_GoodwillAndIntangibleAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationAdditionalInformationAbstract_019d0150-683b-784c-8928-f05e5629b8af" xlink:to="loc_cat_GoodwillAndIntangibleAssets_019d0150-683b-7140-87c9-86e79786ec50" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_PropertyPlantAndEquipmentNetIncludingOtherAssets_019d0150-683b-716c-8da4-85b45680a31e" xlink:href="cat-20260331.xsd#cat_PropertyPlantAndEquipmentNetIncludingOtherAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationAdditionalInformationAbstract_019d0150-683b-784c-8928-f05e5629b8af" xlink:to="loc_cat_PropertyPlantAndEquipmentNetIncludingOtherAssets_019d0150-683b-716c-8da4-85b45680a31e" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_InventoryMethodologyDifference_019d0150-683b-7e9b-89bb-7e87e2ddee77" xlink:href="cat-20260331.xsd#cat_InventoryMethodologyDifference"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingAssetReconcilingItemLineItems_019d0150-683b-7291-a104-048dab0635ff" xlink:to="loc_cat_InventoryMethodologyDifference_019d0150-683b-7e9b-89bb-7e87e2ddee77" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_LiabilitiesIncludedInSegmentsAssets_019d0150-683b-7871-ae85-06e564d220eb" xlink:href="cat-20260331.xsd#cat_LiabilitiesIncludedInSegmentsAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingAssetReconcilingItemLineItems_019d0150-683b-7291-a104-048dab0635ff" xlink:to="loc_cat_LiabilitiesIncludedInSegmentsAssets_019d0150-683b-7871-ae85-06e564d220eb" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherAssets_019d0150-683b-75ce-9af2-9de456d90c86" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingAssetReconcilingItemLineItems_019d0150-683b-7291-a104-048dab0635ff" xlink:to="loc_us-gaap_OtherAssets_019d0150-683b-75ce-9af2-9de456d90c86" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DepreciationDepletionAndAmortization_019dbb45-7117-7483-8d8e-de62c07e5d8d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DepreciationDepletionAndAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingAssetReconcilingItemLineItems_019d0150-683b-7291-a104-048dab0635ff" xlink:to="loc_us-gaap_DepreciationDepletionAndAmortization_019dbb45-7117-7483-8d8e-de62c07e5d8d" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_CostCentersDepreciationDepletionAndAmortization_019dbb45-7117-7878-8fec-ca1f60e29233" xlink:href="cat-20260331.xsd#cat_CostCentersDepreciationDepletionAndAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingAssetReconcilingItemLineItems_019d0150-683b-7291-a104-048dab0635ff" xlink:to="loc_cat_CostCentersDepreciationDepletionAndAmortization_019dbb45-7117-7878-8fec-ca1f60e29233" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherDepreciationAndAmortization_019dbb45-7117-7b2c-807f-c5a69948a581" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherDepreciationAndAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingAssetReconcilingItemLineItems_019d0150-683b-7291-a104-048dab0635ff" xlink:to="loc_us-gaap_OtherDepreciationAndAmortization_019dbb45-7117-7b2c-807f-c5a69948a581" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentExpenditureAdditionToLongLivedAssets_019dbb45-f94b-7e2b-b563-063e1c1bbcb1" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SegmentExpenditureAdditionToLongLivedAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingAssetReconcilingItemLineItems_019d0150-683b-7291-a104-048dab0635ff" xlink:to="loc_us-gaap_SegmentExpenditureAdditionToLongLivedAssets_019dbb45-f94b-7e2b-b563-063e1c1bbcb1" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_CostCentersCapitalExpenditures_019dbb45-f94b-7790-92eb-ba4a553909c2" xlink:href="cat-20260331.xsd#cat_CostCentersCapitalExpenditures"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingAssetReconcilingItemLineItems_019d0150-683b-7291-a104-048dab0635ff" xlink:to="loc_cat_CostCentersCapitalExpenditures_019dbb45-f94b-7790-92eb-ba4a553909c2" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_TimingCapitalExpenditures_019dbb45-f94b-7354-9421-3fa687d539a4" xlink:href="cat-20260331.xsd#cat_TimingCapitalExpenditures"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingAssetReconcilingItemLineItems_019d0150-683b-7291-a104-048dab0635ff" xlink:to="loc_cat_TimingCapitalExpenditures_019dbb45-f94b-7354-9421-3fa687d539a4" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_OtherCapitalExpenditures_019dbb45-f94b-7878-a2aa-302ebd60d965" xlink:href="cat-20260331.xsd#cat_OtherCapitalExpenditures"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingAssetReconcilingItemLineItems_019d0150-683b-7291-a104-048dab0635ff" xlink:to="loc_cat_OtherCapitalExpenditures_019dbb45-f94b-7878-a2aa-302ebd60d965" xlink:type="arc" order="11"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.cat.com/role/SegmentinformationReconciliationsofDepreciationandAmortizationDetails" xlink:type="simple" xlink:href="cat-20260331.xsd#SegmentinformationReconciliationsofDepreciationandAmortizationDetails"/>
  <link:definitionLink xlink:role="http://www.cat.com/role/SegmentinformationReconciliationsofDepreciationandAmortizationDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_cat_SegmentReportingInformationDepreciationDepletionAndAmortizationExpenseLineItems_019d0150-683b-7c62-856b-91c2955bb6b6" xlink:href="cat-20260331.xsd#cat_SegmentReportingInformationDepreciationDepletionAndAmortizationExpenseLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_019d0150-683b-7dcd-97f0-83e8ccd0f31b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_cat_SegmentReportingInformationDepreciationDepletionAndAmortizationExpenseLineItems_019d0150-683b-7c62-856b-91c2955bb6b6" xlink:to="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_019d0150-683b-7dcd-97f0-83e8ccd0f31b" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsAxis_019d0150-683b-74c8-aa8c-5a467d950907" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_ConsolidationItemsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_019d0150-683b-7dcd-97f0-83e8ccd0f31b" xlink:to="loc_srt_ConsolidationItemsAxis_019d0150-683b-74c8-aa8c-5a467d950907" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_019d0150-683b-74c8-aa8c-5a467d950907_default" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_ConsolidationItemsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ConsolidationItemsAxis_019d0150-683b-74c8-aa8c-5a467d950907" xlink:to="loc_srt_ConsolidationItemsDomain_019d0150-683b-74c8-aa8c-5a467d950907_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_019d0150-683b-7f98-ae4f-603c151de4c3" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_ConsolidationItemsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ConsolidationItemsAxis_019d0150-683b-74c8-aa8c-5a467d950907" xlink:to="loc_srt_ConsolidationItemsDomain_019d0150-683b-7f98-ae4f-603c151de4c3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingSegmentsMember_019d0150-683b-70aa-8c56-f5ff80557242" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OperatingSegmentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidationItemsDomain_019d0150-683b-7f98-ae4f-603c151de4c3" xlink:to="loc_us-gaap_OperatingSegmentsMember_019d0150-683b-70aa-8c56-f5ff80557242" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CorporateNonSegmentMember_019d0150-683b-75bb-b520-8d50869a42d3" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CorporateNonSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidationItemsDomain_019d0150-683b-7f98-ae4f-603c151de4c3" xlink:to="loc_us-gaap_CorporateNonSegmentMember_019d0150-683b-75bb-b520-8d50869a42d3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_019d0150-683b-7167-aa50-b0d3163b8bef" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_019d0150-683b-7dcd-97f0-83e8ccd0f31b" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_019d0150-683b-7167-aa50-b0d3163b8bef" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_019d0150-683b-7167-aa50-b0d3163b8bef_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_019d0150-683b-7167-aa50-b0d3163b8bef" xlink:to="loc_us-gaap_SegmentDomain_019d0150-683b-7167-aa50-b0d3163b8bef_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_019d0150-683b-7f5f-b750-fe28789a54d6" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_019d0150-683b-7167-aa50-b0d3163b8bef" xlink:to="loc_us-gaap_SegmentDomain_019d0150-683b-7f5f-b750-fe28789a54d6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_PowerEnergyMember_019d0150-683b-70fe-8e79-bb753c52a44f" xlink:href="cat-20260331.xsd#cat_PowerEnergyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019d0150-683b-7f5f-b750-fe28789a54d6" xlink:to="loc_cat_PowerEnergyMember_019d0150-683b-70fe-8e79-bb753c52a44f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_ConstructionIndustriesMember_019d0150-683b-7a56-af13-65211bb634d5" xlink:href="cat-20260331.xsd#cat_ConstructionIndustriesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019d0150-683b-7f5f-b750-fe28789a54d6" xlink:to="loc_cat_ConstructionIndustriesMember_019d0150-683b-7a56-af13-65211bb634d5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_ResourceIndustriesMember_019d0150-683b-7bc8-bec4-e071d9dd68f7" xlink:href="cat-20260331.xsd#cat_ResourceIndustriesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019d0150-683b-7f5f-b750-fe28789a54d6" xlink:to="loc_cat_ResourceIndustriesMember_019d0150-683b-7bc8-bec4-e071d9dd68f7" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_FinancialProductsSegmentMember_019d0150-683b-7d2c-863a-1c5fae746cd5" xlink:href="cat-20260331.xsd#cat_FinancialProductsSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019d0150-683b-7f5f-b750-fe28789a54d6" xlink:to="loc_cat_FinancialProductsSegmentMember_019d0150-683b-7d2c-863a-1c5fae746cd5" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllOtherSegmentsMember_019d0150-683b-74d9-b146-fce39c63258c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AllOtherSegmentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019d0150-683b-7f5f-b750-fe28789a54d6" xlink:to="loc_us-gaap_AllOtherSegmentsMember_019d0150-683b-74d9-b146-fce39c63258c" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DepreciationAndAmortizationAbstract_019d0150-683b-7fe6-84ea-f2ce9af149cf" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DepreciationAndAmortizationAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cat_SegmentReportingInformationDepreciationDepletionAndAmortizationExpenseLineItems_019d0150-683b-7c62-856b-91c2955bb6b6" xlink:to="loc_us-gaap_DepreciationAndAmortizationAbstract_019d0150-683b-7fe6-84ea-f2ce9af149cf" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DepreciationDepletionAndAmortization_019d0150-683b-7a81-87cd-f69a64eb12c4" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DepreciationDepletionAndAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DepreciationAndAmortizationAbstract_019d0150-683b-7fe6-84ea-f2ce9af149cf" xlink:to="loc_us-gaap_DepreciationDepletionAndAmortization_019d0150-683b-7a81-87cd-f69a64eb12c4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_DepreciationDepletionAndAmortizationSegmentsAbstract_019d0150-683b-7634-8eee-92156166b384" xlink:href="cat-20260331.xsd#cat_DepreciationDepletionAndAmortizationSegmentsAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DepreciationAndAmortizationAbstract_019d0150-683b-7fe6-84ea-f2ce9af149cf" xlink:to="loc_cat_DepreciationDepletionAndAmortizationSegmentsAbstract_019d0150-683b-7634-8eee-92156166b384" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_CostCentersDepreciationDepletionAndAmortization_019d0150-683b-7c44-b9e3-7638ea42eaad" xlink:href="cat-20260331.xsd#cat_CostCentersDepreciationDepletionAndAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cat_DepreciationDepletionAndAmortizationSegmentsAbstract_019d0150-683b-7634-8eee-92156166b384" xlink:to="loc_cat_CostCentersDepreciationDepletionAndAmortization_019d0150-683b-7c44-b9e3-7638ea42eaad" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherDepreciationAndAmortization_019d0150-683b-77f3-912a-6abcabd741c3" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherDepreciationAndAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cat_DepreciationDepletionAndAmortizationSegmentsAbstract_019d0150-683b-7634-8eee-92156166b384" xlink:to="loc_us-gaap_OtherDepreciationAndAmortization_019d0150-683b-77f3-912a-6abcabd741c3" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.cat.com/role/SegmentinformationReconciliationsofCapitalExpendituresDetails" xlink:type="simple" xlink:href="cat-20260331.xsd#SegmentinformationReconciliationsofCapitalExpendituresDetails"/>
  <link:definitionLink xlink:role="http://www.cat.com/role/SegmentinformationReconciliationsofCapitalExpendituresDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_cat_SegmentReportingInformationCapitalExpenditureLineItems_019d0150-683b-7c36-8312-30341dee7621" xlink:href="cat-20260331.xsd#cat_SegmentReportingInformationCapitalExpenditureLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_019d0150-683b-7849-a65d-72e800dfdbf4" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_cat_SegmentReportingInformationCapitalExpenditureLineItems_019d0150-683b-7c36-8312-30341dee7621" xlink:to="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_019d0150-683b-7849-a65d-72e800dfdbf4" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsAxis_019d0150-683b-7375-867d-fadf60dc7ce0" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_ConsolidationItemsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_019d0150-683b-7849-a65d-72e800dfdbf4" xlink:to="loc_srt_ConsolidationItemsAxis_019d0150-683b-7375-867d-fadf60dc7ce0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_019d0150-683b-7375-867d-fadf60dc7ce0_default" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_ConsolidationItemsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ConsolidationItemsAxis_019d0150-683b-7375-867d-fadf60dc7ce0" xlink:to="loc_srt_ConsolidationItemsDomain_019d0150-683b-7375-867d-fadf60dc7ce0_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_019d0150-683b-7646-9522-9803f63a0f49" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_ConsolidationItemsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ConsolidationItemsAxis_019d0150-683b-7375-867d-fadf60dc7ce0" xlink:to="loc_srt_ConsolidationItemsDomain_019d0150-683b-7646-9522-9803f63a0f49" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingSegmentsMember_019d0150-683b-7a7f-90b4-f7bb3cd8a82e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OperatingSegmentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidationItemsDomain_019d0150-683b-7646-9522-9803f63a0f49" xlink:to="loc_us-gaap_OperatingSegmentsMember_019d0150-683b-7a7f-90b4-f7bb3cd8a82e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CorporateNonSegmentMember_019d0150-683b-7b55-b964-e7c2404aedcf" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CorporateNonSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidationItemsDomain_019d0150-683b-7646-9522-9803f63a0f49" xlink:to="loc_us-gaap_CorporateNonSegmentMember_019d0150-683b-7b55-b964-e7c2404aedcf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_019d0150-683b-71bb-bcae-3982a5ee3ebc" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_019d0150-683b-7849-a65d-72e800dfdbf4" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_019d0150-683b-71bb-bcae-3982a5ee3ebc" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_019d0150-683b-71bb-bcae-3982a5ee3ebc_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_019d0150-683b-71bb-bcae-3982a5ee3ebc" xlink:to="loc_us-gaap_SegmentDomain_019d0150-683b-71bb-bcae-3982a5ee3ebc_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_019d0150-683b-7783-a2ab-995a04f8bc8a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_019d0150-683b-71bb-bcae-3982a5ee3ebc" xlink:to="loc_us-gaap_SegmentDomain_019d0150-683b-7783-a2ab-995a04f8bc8a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_ConstructionIndustriesMember_019d0150-683b-7a4e-be23-abb15cbd385f" xlink:href="cat-20260331.xsd#cat_ConstructionIndustriesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019d0150-683b-7783-a2ab-995a04f8bc8a" xlink:to="loc_cat_ConstructionIndustriesMember_019d0150-683b-7a4e-be23-abb15cbd385f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_ResourceIndustriesMember_019d0150-683b-7861-9e7d-341280123407" xlink:href="cat-20260331.xsd#cat_ResourceIndustriesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019d0150-683b-7783-a2ab-995a04f8bc8a" xlink:to="loc_cat_ResourceIndustriesMember_019d0150-683b-7861-9e7d-341280123407" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_PowerEnergyMember_019d0150-683b-78fd-b33f-e63db13af992" xlink:href="cat-20260331.xsd#cat_PowerEnergyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019d0150-683b-7783-a2ab-995a04f8bc8a" xlink:to="loc_cat_PowerEnergyMember_019d0150-683b-78fd-b33f-e63db13af992" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_FinancialProductsSegmentMember_019d0150-683b-7cb1-a736-7ed183e131ac" xlink:href="cat-20260331.xsd#cat_FinancialProductsSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019d0150-683b-7783-a2ab-995a04f8bc8a" xlink:to="loc_cat_FinancialProductsSegmentMember_019d0150-683b-7cb1-a736-7ed183e131ac" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllOtherSegmentsMember_019d0150-683b-7c25-9ead-e00433406532" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AllOtherSegmentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019d0150-683b-7783-a2ab-995a04f8bc8a" xlink:to="loc_us-gaap_AllOtherSegmentsMember_019d0150-683b-7c25-9ead-e00433406532" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_SegmentReportingInformationCapitalExpenditureAbstract_019d0150-683b-70c0-83ab-19f05baea2a5" xlink:href="cat-20260331.xsd#cat_SegmentReportingInformationCapitalExpenditureAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cat_SegmentReportingInformationCapitalExpenditureLineItems_019d0150-683b-7c36-8312-30341dee7621" xlink:to="loc_cat_SegmentReportingInformationCapitalExpenditureAbstract_019d0150-683b-70c0-83ab-19f05baea2a5" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentExpenditureAdditionToLongLivedAssets_019d0150-683b-7bed-af07-6c7efba324b4" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SegmentExpenditureAdditionToLongLivedAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cat_SegmentReportingInformationCapitalExpenditureAbstract_019d0150-683b-70c0-83ab-19f05baea2a5" xlink:to="loc_us-gaap_SegmentExpenditureAdditionToLongLivedAssets_019d0150-683b-7bed-af07-6c7efba324b4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_CapitalExpendituresSegmentsAbstract_019d0150-683b-756b-8b5d-2a94fd991c17" xlink:href="cat-20260331.xsd#cat_CapitalExpendituresSegmentsAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cat_SegmentReportingInformationCapitalExpenditureAbstract_019d0150-683b-70c0-83ab-19f05baea2a5" xlink:to="loc_cat_CapitalExpendituresSegmentsAbstract_019d0150-683b-756b-8b5d-2a94fd991c17" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_CostCentersCapitalExpenditures_019d0150-683b-739e-b816-74381c0e0d5e" xlink:href="cat-20260331.xsd#cat_CostCentersCapitalExpenditures"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cat_CapitalExpendituresSegmentsAbstract_019d0150-683b-756b-8b5d-2a94fd991c17" xlink:to="loc_cat_CostCentersCapitalExpenditures_019d0150-683b-739e-b816-74381c0e0d5e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_TimingCapitalExpenditures_019d0150-683b-77dc-8745-25781f2ec442" xlink:href="cat-20260331.xsd#cat_TimingCapitalExpenditures"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cat_CapitalExpendituresSegmentsAbstract_019d0150-683b-756b-8b5d-2a94fd991c17" xlink:to="loc_cat_TimingCapitalExpenditures_019d0150-683b-77dc-8745-25781f2ec442" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_OtherCapitalExpenditures_019d0150-683b-7193-9dad-515d6f44d683" xlink:href="cat-20260331.xsd#cat_OtherCapitalExpenditures"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cat_CapitalExpendituresSegmentsAbstract_019d0150-683b-756b-8b5d-2a94fd991c17" xlink:to="loc_cat_OtherCapitalExpenditures_019d0150-683b-7193-9dad-515d6f44d683" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.cat.com/role/CatFinancialFinancingActivitiesAllowanceForCreditLossesDetails" xlink:type="simple" xlink:href="cat-20260331.xsd#CatFinancialFinancingActivitiesAllowanceForCreditLossesDetails"/>
  <link:definitionLink xlink:role="http://www.cat.com/role/CatFinancialFinancingActivitiesAllowanceForCreditLossesDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems_019d0150-683b-7f69-824f-d79c8c2d413a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfFinancingReceivableAllowanceForCreditLossesTable_019d0150-683b-7639-a0da-e04aaf0a94d5" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfFinancingReceivableAllowanceForCreditLossesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems_019d0150-683b-7f69-824f-d79c8c2d413a" xlink:to="loc_us-gaap_ScheduleOfFinancingReceivableAllowanceForCreditLossesTable_019d0150-683b-7639-a0da-e04aaf0a94d5" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_019d0150-683b-7f98-8bc0-79dcb63e1e9c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancingReceivablePortfolioSegmentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivableAllowanceForCreditLossesTable_019d0150-683b-7639-a0da-e04aaf0a94d5" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_019d0150-683b-7f98-8bc0-79dcb63e1e9c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019d0150-683b-7f98-8bc0-79dcb63e1e9c_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_019d0150-683b-7f98-8bc0-79dcb63e1e9c" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019d0150-683b-7f98-8bc0-79dcb63e1e9c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019d0150-683b-7cbb-abe6-945de4f6c0e9" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_019d0150-683b-7f98-8bc0-79dcb63e1e9c" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019d0150-683b-7cbb-abe6-945de4f6c0e9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_CustomerMember_019d0150-683b-7fb6-a711-2c7ed4e46ec4" xlink:href="cat-20260331.xsd#cat_CustomerMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019d0150-683b-7cbb-abe6-945de4f6c0e9" xlink:to="loc_cat_CustomerMember_019d0150-683b-7fb6-a711-2c7ed4e46ec4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_DealerMember_019d0150-683b-70be-a1d4-6c795b7976af" xlink:href="cat-20260331.xsd#cat_DealerMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019d0150-683b-7cbb-abe6-945de4f6c0e9" xlink:to="loc_cat_DealerMember_019d0150-683b-70be-a1d4-6c795b7976af" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019d0150-683b-790f-988b-d5b658af40af" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivableAllowanceForCreditLossesTable_019d0150-683b-7639-a0da-e04aaf0a94d5" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019d0150-683b-790f-988b-d5b658af40af" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019d0150-683b-790f-988b-d5b658af40af_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019d0150-683b-790f-988b-d5b658af40af" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019d0150-683b-790f-988b-d5b658af40af_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019d0150-683b-7909-9c72-71fbcf39548c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019d0150-683b-790f-988b-d5b658af40af" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019d0150-683b-7909-9c72-71fbcf39548c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_LatinAmericaMember_019d0150-683b-7ff2-b7c9-a9314d7c10d0" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_LatinAmericaMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019d0150-683b-7909-9c72-71fbcf39548c" xlink:to="loc_srt_LatinAmericaMember_019d0150-683b-7ff2-b7c9-a9314d7c10d0" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesRollForward_019d0150-683b-7188-aa29-d43ea962579c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancingReceivableAllowanceForCreditLossesRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems_019d0150-683b-7f69-824f-d79c8c2d413a" xlink:to="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesRollForward_019d0150-683b-7188-aa29-d43ea962579c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableAllowanceForCreditLosses_019d0150-683b-757f-9b9c-d0b83dd98855" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancingReceivableAllowanceForCreditLosses"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesRollForward_019d0150-683b-7188-aa29-d43ea962579c" xlink:to="loc_us-gaap_FinancingReceivableAllowanceForCreditLosses_019d0150-683b-757f-9b9c-d0b83dd98855" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesWriteOffs_019d0150-683b-7d86-96de-ab6878c242ad" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancingReceivableAllowanceForCreditLossesWriteOffs"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesRollForward_019d0150-683b-7188-aa29-d43ea962579c" xlink:to="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesWriteOffs_019d0150-683b-7d86-96de-ab6878c242ad" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesRecovery_019d0150-683b-71c9-baf6-4088754910a4" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancingReceivableAllowanceForCreditLossesRecovery"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesRollForward_019d0150-683b-7188-aa29-d43ea962579c" xlink:to="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesRecovery_019d0150-683b-71c9-baf6-4088754910a4" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProvisionForLoanLossesExpensed_019d0150-683b-7abc-a105-d530c87b5cb8" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ProvisionForLoanLossesExpensed"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesRollForward_019d0150-683b-7188-aa29-d43ea962579c" xlink:to="loc_us-gaap_ProvisionForLoanLossesExpensed_019d0150-683b-7abc-a105-d530c87b5cb8" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_FinancingReceivableAllowanceForCreditLossesOtherActivity_019d0150-683b-7875-af40-193b419b0fb8" xlink:href="cat-20260331.xsd#cat_FinancingReceivableAllowanceForCreditLossesOtherActivity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesRollForward_019d0150-683b-7188-aa29-d43ea962579c" xlink:to="loc_cat_FinancingReceivableAllowanceForCreditLossesOtherActivity_019d0150-683b-7875-af40-193b419b0fb8" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableAllowanceForCreditLosses_019d0150-683b-7edc-86cf-51f300630705" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancingReceivableAllowanceForCreditLosses"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NotesReceivableGross_019d0150-683b-716a-920e-11f0f5afe5a1" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NotesReceivableGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems_019d0150-683b-7f69-824f-d79c8c2d413a" xlink:to="loc_us-gaap_NotesReceivableGross_019d0150-683b-716a-920e-11f0f5afe5a1" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.cat.com/role/CatFinancialFinancingActivitiesWriteOffsDetails" xlink:type="simple" xlink:href="cat-20260331.xsd#CatFinancialFinancingActivitiesWriteOffsDetails"/>
  <link:definitionLink xlink:role="http://www.cat.com/role/CatFinancialFinancingActivitiesWriteOffsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_cat_WriteOffsByOriginationYearLineItems_019d0150-683b-78f2-9c9b-35366eb9e456" xlink:href="cat-20260331.xsd#cat_WriteOffsByOriginationYearLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_WriteOffsByOriginationYearTable_019d0150-683b-727e-8b5b-f7e3b48d9e5a" xlink:href="cat-20260331.xsd#cat_WriteOffsByOriginationYearTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_cat_WriteOffsByOriginationYearLineItems_019d0150-683b-78f2-9c9b-35366eb9e456" xlink:to="loc_cat_WriteOffsByOriginationYearTable_019d0150-683b-727e-8b5b-f7e3b48d9e5a" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_019d0150-683b-73bf-97ea-c2a33d69cd91" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancingReceivablePortfolioSegmentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_cat_WriteOffsByOriginationYearTable_019d0150-683b-727e-8b5b-f7e3b48d9e5a" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_019d0150-683b-73bf-97ea-c2a33d69cd91" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019d0150-683b-73bf-97ea-c2a33d69cd91_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_019d0150-683b-73bf-97ea-c2a33d69cd91" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019d0150-683b-73bf-97ea-c2a33d69cd91_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019d0150-683b-70e8-8528-e8256e19b456" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_019d0150-683b-73bf-97ea-c2a33d69cd91" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019d0150-683b-70e8-8528-e8256e19b456" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_CustomerMember_019d0150-683b-7d08-90dc-594b4fdc9a2e" xlink:href="cat-20260331.xsd#cat_CustomerMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019d0150-683b-70e8-8528-e8256e19b456" xlink:to="loc_cat_CustomerMember_019d0150-683b-7d08-90dc-594b4fdc9a2e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_DealerMember_019d0150-683b-75b9-8c96-264335eae34f" xlink:href="cat-20260331.xsd#cat_DealerMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019d0150-683b-70e8-8528-e8256e19b456" xlink:to="loc_cat_DealerMember_019d0150-683b-75b9-8c96-264335eae34f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019d0150-683b-77d5-a5c9-725e642fcb35" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_cat_WriteOffsByOriginationYearTable_019d0150-683b-727e-8b5b-f7e3b48d9e5a" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019d0150-683b-77d5-a5c9-725e642fcb35" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019d0150-683b-77d5-a5c9-725e642fcb35_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019d0150-683b-77d5-a5c9-725e642fcb35" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019d0150-683b-77d5-a5c9-725e642fcb35_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019d0150-683b-756d-ae9b-10b0c687e3c6" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019d0150-683b-77d5-a5c9-725e642fcb35" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019d0150-683b-756d-ae9b-10b0c687e3c6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_NorthAmericaMember_019d0150-683b-7c21-858f-9bd58a4243bf" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_NorthAmericaMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019d0150-683b-756d-ae9b-10b0c687e3c6" xlink:to="loc_srt_NorthAmericaMember_019d0150-683b-7c21-858f-9bd58a4243bf" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EMEAMember_019d0150-683b-7471-b027-1fd2c5091314" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EMEAMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019d0150-683b-756d-ae9b-10b0c687e3c6" xlink:to="loc_us-gaap_EMEAMember_019d0150-683b-7471-b027-1fd2c5091314" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_AsiaPacificMember_019d0150-683b-77ea-92aa-50fc02c4b086" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_AsiaPacificMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019d0150-683b-756d-ae9b-10b0c687e3c6" xlink:to="loc_srt_AsiaPacificMember_019d0150-683b-77ea-92aa-50fc02c4b086" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_LatinAmericaMember_019d0150-683b-7ba9-8ae5-0afba8525624" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_LatinAmericaMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019d0150-683b-756d-ae9b-10b0c687e3c6" xlink:to="loc_srt_LatinAmericaMember_019d0150-683b-7ba9-8ae5-0afba8525624" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_MiningMember_019d0150-683b-77a2-809c-12222bd0b92e" xlink:href="cat-20260331.xsd#cat_MiningMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019d0150-683b-756d-ae9b-10b0c687e3c6" xlink:to="loc_cat_MiningMember_019d0150-683b-77a2-809c-12222bd0b92e" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_PowerMember_019d0150-683b-7bc4-b80a-3a0228a92d4d" xlink:href="cat-20260331.xsd#cat_PowerMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019d0150-683b-756d-ae9b-10b0c687e3c6" xlink:to="loc_cat_PowerMember_019d0150-683b-7bc4-b80a-3a0228a92d4d" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableYearOneOriginatedCurrentFiscalYearWriteoff_019d0150-683b-7173-ba67-d1ef0ce6882c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancingReceivableYearOneOriginatedCurrentFiscalYearWriteoff"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cat_WriteOffsByOriginationYearLineItems_019d0150-683b-78f2-9c9b-35366eb9e456" xlink:to="loc_us-gaap_FinancingReceivableYearOneOriginatedCurrentFiscalYearWriteoff_019d0150-683b-7173-ba67-d1ef0ce6882c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableYearTwoOriginatedFiscalYearBeforeCurrentFiscalYearWriteoff_019d0150-683b-7736-9115-a7d883672921" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancingReceivableYearTwoOriginatedFiscalYearBeforeCurrentFiscalYearWriteoff"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cat_WriteOffsByOriginationYearLineItems_019d0150-683b-78f2-9c9b-35366eb9e456" xlink:to="loc_us-gaap_FinancingReceivableYearTwoOriginatedFiscalYearBeforeCurrentFiscalYearWriteoff_019d0150-683b-7736-9115-a7d883672921" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableYearThreeOriginatedTwoYearsBeforeCurrentFiscalYearWriteoff_019d0150-683b-77cb-bcbd-6c841dc4a5bc" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancingReceivableYearThreeOriginatedTwoYearsBeforeCurrentFiscalYearWriteoff"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cat_WriteOffsByOriginationYearLineItems_019d0150-683b-78f2-9c9b-35366eb9e456" xlink:to="loc_us-gaap_FinancingReceivableYearThreeOriginatedTwoYearsBeforeCurrentFiscalYearWriteoff_019d0150-683b-77cb-bcbd-6c841dc4a5bc" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableYearFourOriginatedThreeYearsBeforeCurrentFiscalYearWriteoff_019d0150-683b-718c-9e76-eec5618bfbb3" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancingReceivableYearFourOriginatedThreeYearsBeforeCurrentFiscalYearWriteoff"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cat_WriteOffsByOriginationYearLineItems_019d0150-683b-78f2-9c9b-35366eb9e456" xlink:to="loc_us-gaap_FinancingReceivableYearFourOriginatedThreeYearsBeforeCurrentFiscalYearWriteoff_019d0150-683b-718c-9e76-eec5618bfbb3" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableYearFiveOriginatedFourYearsBeforeCurrentFiscalYearWriteoff_019d0150-683b-7c0f-9ca7-82c0ae2f984b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancingReceivableYearFiveOriginatedFourYearsBeforeCurrentFiscalYearWriteoff"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cat_WriteOffsByOriginationYearLineItems_019d0150-683b-78f2-9c9b-35366eb9e456" xlink:to="loc_us-gaap_FinancingReceivableYearFiveOriginatedFourYearsBeforeCurrentFiscalYearWriteoff_019d0150-683b-7c0f-9ca7-82c0ae2f984b" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableOriginatedMoreThanFiveYearsBeforeCurrentFiscalYearWriteoff_019d0150-683b-7c2c-8b70-9f4d8b519ef2" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancingReceivableOriginatedMoreThanFiveYearsBeforeCurrentFiscalYearWriteoff"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cat_WriteOffsByOriginationYearLineItems_019d0150-683b-78f2-9c9b-35366eb9e456" xlink:to="loc_us-gaap_FinancingReceivableOriginatedMoreThanFiveYearsBeforeCurrentFiscalYearWriteoff_019d0150-683b-7c2c-8b70-9f4d8b519ef2" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRevolvingWriteoff_019d0150-683b-7234-8701-af1f37e0ff2d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancingReceivableRevolvingWriteoff"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cat_WriteOffsByOriginationYearLineItems_019d0150-683b-78f2-9c9b-35366eb9e456" xlink:to="loc_us-gaap_FinancingReceivableRevolvingWriteoff_019d0150-683b-7234-8701-af1f37e0ff2d" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesWriteOffs_019d0150-683b-7ebf-90ec-a6a185c367ad" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancingReceivableAllowanceForCreditLossesWriteOffs"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cat_WriteOffsByOriginationYearLineItems_019d0150-683b-78f2-9c9b-35366eb9e456" xlink:to="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesWriteOffs_019d0150-683b-7ebf-90ec-a6a185c367ad" xlink:type="arc" order="7"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.cat.com/role/CatFinancialFinancingActivitiesFinancingReceivableCreditQualityIndicatorDetails" xlink:type="simple" xlink:href="cat-20260331.xsd#CatFinancialFinancingActivitiesFinancingReceivableCreditQualityIndicatorDetails"/>
  <link:definitionLink xlink:role="http://www.cat.com/role/CatFinancialFinancingActivitiesFinancingReceivableCreditQualityIndicatorDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_019d0150-683b-7d93-bacb-b31245a6bba5" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancingReceivableRecordedInvestmentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable_019d0150-683b-7033-9b19-de74b298424f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_019d0150-683b-7d93-bacb-b31245a6bba5" xlink:to="loc_us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable_019d0150-683b-7033-9b19-de74b298424f" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_019d0150-683b-7334-9f62-cb6afadcb510" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancingReceivablePortfolioSegmentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable_019d0150-683b-7033-9b19-de74b298424f" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_019d0150-683b-7334-9f62-cb6afadcb510" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019d0150-683b-7334-9f62-cb6afadcb510_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_019d0150-683b-7334-9f62-cb6afadcb510" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019d0150-683b-7334-9f62-cb6afadcb510_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019d0150-683b-7b67-8de2-868e824a77b7" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_019d0150-683b-7334-9f62-cb6afadcb510" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019d0150-683b-7b67-8de2-868e824a77b7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_CustomerMember_019d0150-683b-7314-802d-90aabf78a758" xlink:href="cat-20260331.xsd#cat_CustomerMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019d0150-683b-7b67-8de2-868e824a77b7" xlink:to="loc_cat_CustomerMember_019d0150-683b-7314-802d-90aabf78a758" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019d0150-683b-74c7-ab98-2dc589f216b9" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable_019d0150-683b-7033-9b19-de74b298424f" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019d0150-683b-74c7-ab98-2dc589f216b9" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019d0150-683b-74c7-ab98-2dc589f216b9_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019d0150-683b-74c7-ab98-2dc589f216b9" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019d0150-683b-74c7-ab98-2dc589f216b9_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019d0150-683b-790a-9021-95ab2760b2b5" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019d0150-683b-74c7-ab98-2dc589f216b9" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019d0150-683b-790a-9021-95ab2760b2b5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_NorthAmericaMember_019d0150-683b-7196-b735-6d145cdf4231" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_NorthAmericaMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019d0150-683b-790a-9021-95ab2760b2b5" xlink:to="loc_srt_NorthAmericaMember_019d0150-683b-7196-b735-6d145cdf4231" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EMEAMember_019d0150-683b-74ed-901d-441dde0ccebc" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EMEAMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019d0150-683b-790a-9021-95ab2760b2b5" xlink:to="loc_us-gaap_EMEAMember_019d0150-683b-74ed-901d-441dde0ccebc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_AsiaPacificMember_019d0150-683b-7f8b-a3da-6ef81cb79eee" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_AsiaPacificMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019d0150-683b-790a-9021-95ab2760b2b5" xlink:to="loc_srt_AsiaPacificMember_019d0150-683b-7f8b-a3da-6ef81cb79eee" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_LatinAmericaMember_019d0150-683b-76a0-bd9a-1419ea6ceb2c" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_LatinAmericaMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019d0150-683b-790a-9021-95ab2760b2b5" xlink:to="loc_srt_LatinAmericaMember_019d0150-683b-76a0-bd9a-1419ea6ceb2c" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_MiningMember_019d0150-683b-7f54-9e98-a68651451ab9" xlink:href="cat-20260331.xsd#cat_MiningMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019d0150-683b-790a-9021-95ab2760b2b5" xlink:to="loc_cat_MiningMember_019d0150-683b-7f54-9e98-a68651451ab9" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_PowerMember_019d0150-683b-71a3-920e-e9b4f9fee6d4" xlink:href="cat-20260331.xsd#cat_PowerMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019d0150-683b-790a-9021-95ab2760b2b5" xlink:to="loc_cat_PowerMember_019d0150-683b-71a3-920e-e9b4f9fee6d4" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InternalCreditAssessmentAxis_019d0150-683b-7a70-9929-b780cad59b5e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_InternalCreditAssessmentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable_019d0150-683b-7033-9b19-de74b298424f" xlink:to="loc_us-gaap_InternalCreditAssessmentAxis_019d0150-683b-7a70-9929-b780cad59b5e" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InternalCreditAssessmentDomain_019d0150-683b-7a70-9929-b780cad59b5e_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_InternalCreditAssessmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_InternalCreditAssessmentAxis_019d0150-683b-7a70-9929-b780cad59b5e" xlink:to="loc_us-gaap_InternalCreditAssessmentDomain_019d0150-683b-7a70-9929-b780cad59b5e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InternalCreditAssessmentDomain_019d0150-683b-7ef9-8f1d-a82a96cafec9" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_InternalCreditAssessmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_InternalCreditAssessmentAxis_019d0150-683b-7a70-9929-b780cad59b5e" xlink:to="loc_us-gaap_InternalCreditAssessmentDomain_019d0150-683b-7ef9-8f1d-a82a96cafec9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_CurrentMember_019d0150-683b-7604-b37c-3b4a655123dc" xlink:href="cat-20260331.xsd#cat_CurrentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InternalCreditAssessmentDomain_019d0150-683b-7ef9-8f1d-a82a96cafec9" xlink:to="loc_cat_CurrentMember_019d0150-683b-7604-b37c-3b4a655123dc" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_FinancingReceivables31to60DaysPastDueMember_019d0150-683b-70c1-b496-15264c89c768" xlink:href="cat-20260331.xsd#cat_FinancingReceivables31to60DaysPastDueMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InternalCreditAssessmentDomain_019d0150-683b-7ef9-8f1d-a82a96cafec9" xlink:to="loc_cat_FinancingReceivables31to60DaysPastDueMember_019d0150-683b-70c1-b496-15264c89c768" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_FinancingReceivables61to90DaysPastDueMember_019d0150-683b-7618-9b35-85562233ea9a" xlink:href="cat-20260331.xsd#cat_FinancingReceivables61to90DaysPastDueMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InternalCreditAssessmentDomain_019d0150-683b-7ef9-8f1d-a82a96cafec9" xlink:to="loc_cat_FinancingReceivables61to90DaysPastDueMember_019d0150-683b-7618-9b35-85562233ea9a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_FinancingReceivablesEqualtoGreaterthan91DaysPastDueMember_019d0150-683b-75e3-a53e-4b4c263d2064" xlink:href="cat-20260331.xsd#cat_FinancingReceivablesEqualtoGreaterthan91DaysPastDueMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InternalCreditAssessmentDomain_019d0150-683b-7ef9-8f1d-a82a96cafec9" xlink:to="loc_cat_FinancingReceivablesEqualtoGreaterthan91DaysPastDueMember_019d0150-683b-75e3-a53e-4b4c263d2064" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableOriginatedInCurrentFiscalYear_019d0150-683b-7a15-9745-c9f2e6b8a8cc" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancingReceivableOriginatedInCurrentFiscalYear"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_019d0150-683b-7d93-bacb-b31245a6bba5" xlink:to="loc_us-gaap_FinancingReceivableOriginatedInCurrentFiscalYear_019d0150-683b-7a15-9745-c9f2e6b8a8cc" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableOriginatedInFiscalYearBeforeLatestFiscalYear_019d0150-683b-7831-aa5b-a10f2542028f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancingReceivableOriginatedInFiscalYearBeforeLatestFiscalYear"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_019d0150-683b-7d93-bacb-b31245a6bba5" xlink:to="loc_us-gaap_FinancingReceivableOriginatedInFiscalYearBeforeLatestFiscalYear_019d0150-683b-7831-aa5b-a10f2542028f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableOriginatedTwoYearsBeforeLatestFiscalYear_019d0150-683b-7957-8250-803e4dfa8486" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancingReceivableOriginatedTwoYearsBeforeLatestFiscalYear"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_019d0150-683b-7d93-bacb-b31245a6bba5" xlink:to="loc_us-gaap_FinancingReceivableOriginatedTwoYearsBeforeLatestFiscalYear_019d0150-683b-7957-8250-803e4dfa8486" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableOriginatedThreeYearsBeforeLatestFiscalYear_019d0150-683b-746d-960e-44650ff36451" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancingReceivableOriginatedThreeYearsBeforeLatestFiscalYear"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_019d0150-683b-7d93-bacb-b31245a6bba5" xlink:to="loc_us-gaap_FinancingReceivableOriginatedThreeYearsBeforeLatestFiscalYear_019d0150-683b-746d-960e-44650ff36451" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableOriginatedFourYearsBeforeLatestFiscalYear_019d0150-683b-70fd-81a8-852193a57539" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancingReceivableOriginatedFourYearsBeforeLatestFiscalYear"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_019d0150-683b-7d93-bacb-b31245a6bba5" xlink:to="loc_us-gaap_FinancingReceivableOriginatedFourYearsBeforeLatestFiscalYear_019d0150-683b-70fd-81a8-852193a57539" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableOriginatedFiveOrMoreYearsBeforeLatestFiscalYear_019d0150-683b-7be7-9aaf-1dc97ff2e4d5" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancingReceivableOriginatedFiveOrMoreYearsBeforeLatestFiscalYear"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_019d0150-683b-7d93-bacb-b31245a6bba5" xlink:to="loc_us-gaap_FinancingReceivableOriginatedFiveOrMoreYearsBeforeLatestFiscalYear_019d0150-683b-7be7-9aaf-1dc97ff2e4d5" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRevolving_019d0150-683b-70bf-a456-8071ccfd2619" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancingReceivableRevolving"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_019d0150-683b-7d93-bacb-b31245a6bba5" xlink:to="loc_us-gaap_FinancingReceivableRevolving_019d0150-683b-70bf-a456-8071ccfd2619" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NotesReceivableGross_019d0150-683b-7a69-b899-1b9673fd46c5" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NotesReceivableGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_019d0150-683b-7d93-bacb-b31245a6bba5" xlink:to="loc_us-gaap_NotesReceivableGross_019d0150-683b-7a69-b899-1b9673fd46c5" xlink:type="arc" order="7"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.cat.com/role/CatFinancialFinancingActivitiesInvestmentInFinanceReceivablesOnNonAccrualStatusDetails" xlink:type="simple" xlink:href="cat-20260331.xsd#CatFinancialFinancingActivitiesInvestmentInFinanceReceivablesOnNonAccrualStatusDetails"/>
  <link:definitionLink xlink:role="http://www.cat.com/role/CatFinancialFinancingActivitiesInvestmentInFinanceReceivablesOnNonAccrualStatusDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableNonaccrualStatusLineItems_019d0150-683b-72d7-9b45-1f8cd6b63082" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancingReceivableNonaccrualStatusLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableNonaccrualTable_019d0150-683b-7155-bd48-f64045886401" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancingReceivableNonaccrualTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FinancingReceivableNonaccrualStatusLineItems_019d0150-683b-72d7-9b45-1f8cd6b63082" xlink:to="loc_us-gaap_FinancingReceivableNonaccrualTable_019d0150-683b-7155-bd48-f64045886401" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019d0150-683b-7559-9e2a-94932eebfe7a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FinancingReceivableNonaccrualTable_019d0150-683b-7155-bd48-f64045886401" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019d0150-683b-7559-9e2a-94932eebfe7a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019d0150-683b-7559-9e2a-94932eebfe7a_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019d0150-683b-7559-9e2a-94932eebfe7a" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019d0150-683b-7559-9e2a-94932eebfe7a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019d0150-683b-741f-8cd7-36719bc15a1a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019d0150-683b-7559-9e2a-94932eebfe7a" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019d0150-683b-741f-8cd7-36719bc15a1a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_NorthAmericaMember_019d0150-683b-7885-9208-4b4c24332d96" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_NorthAmericaMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019d0150-683b-741f-8cd7-36719bc15a1a" xlink:to="loc_srt_NorthAmericaMember_019d0150-683b-7885-9208-4b4c24332d96" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EMEAMember_019d0150-683b-7811-83dd-02934a86f929" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EMEAMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019d0150-683b-741f-8cd7-36719bc15a1a" xlink:to="loc_us-gaap_EMEAMember_019d0150-683b-7811-83dd-02934a86f929" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_AsiaPacificMember_019d0150-683b-77d6-ac36-3e73c48cf6af" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_AsiaPacificMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019d0150-683b-741f-8cd7-36719bc15a1a" xlink:to="loc_srt_AsiaPacificMember_019d0150-683b-77d6-ac36-3e73c48cf6af" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_LatinAmericaMember_019d0150-683b-7cfb-a989-843e6917bab2" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_LatinAmericaMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019d0150-683b-741f-8cd7-36719bc15a1a" xlink:to="loc_srt_LatinAmericaMember_019d0150-683b-7cfb-a989-843e6917bab2" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_MiningMember_019d0150-683b-7dcf-8653-8e6c17917e63" xlink:href="cat-20260331.xsd#cat_MiningMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019d0150-683b-741f-8cd7-36719bc15a1a" xlink:to="loc_cat_MiningMember_019d0150-683b-7dcf-8653-8e6c17917e63" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_019d0150-683b-7025-8c93-3f5681ec6933" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancingReceivablePortfolioSegmentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FinancingReceivableNonaccrualTable_019d0150-683b-7155-bd48-f64045886401" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_019d0150-683b-7025-8c93-3f5681ec6933" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019d0150-683b-7025-8c93-3f5681ec6933_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_019d0150-683b-7025-8c93-3f5681ec6933" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019d0150-683b-7025-8c93-3f5681ec6933_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019d0150-683b-75be-812f-8e0a1e192f2c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_019d0150-683b-7025-8c93-3f5681ec6933" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019d0150-683b-75be-812f-8e0a1e192f2c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_DealerMember_019d0150-683b-7161-a89f-8a3091ab0359" xlink:href="cat-20260331.xsd#cat_DealerMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019d0150-683b-75be-812f-8e0a1e192f2c" xlink:to="loc_cat_DealerMember_019d0150-683b-7161-a89f-8a3091ab0359" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_CustomerMember_019d0150-683b-7b37-82ab-40ac7336602f" xlink:href="cat-20260331.xsd#cat_CustomerMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019d0150-683b-75be-812f-8e0a1e192f2c" xlink:to="loc_cat_CustomerMember_019d0150-683b-7b37-82ab-40ac7336602f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_PeriodAfterWhichCollectionOfFutureIncomeIsConsideredAsNotProbable_019d0150-683b-7faa-aee9-ab5b88c934bc" xlink:href="cat-20260331.xsd#cat_PeriodAfterWhichCollectionOfFutureIncomeIsConsideredAsNotProbable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableNonaccrualStatusLineItems_019d0150-683b-72d7-9b45-1f8cd6b63082" xlink:to="loc_cat_PeriodAfterWhichCollectionOfFutureIncomeIsConsideredAsNotProbable_019d0150-683b-7faa-aee9-ab5b88c934bc" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus_019d0150-683b-7b34-b450-a3b4b1dc0d1e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableNonaccrualStatusLineItems_019d0150-683b-72d7-9b45-1f8cd6b63082" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus_019d0150-683b-7b34-b450-a3b4b1dc0d1e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_FinancingReceivable91dayspastdueandstillaccruing_019d0150-683b-703b-8b42-055cab09ee10" xlink:href="cat-20260331.xsd#cat_FinancingReceivable91dayspastdueandstillaccruing"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableNonaccrualStatusLineItems_019d0150-683b-72d7-9b45-1f8cd6b63082" xlink:to="loc_cat_FinancingReceivable91dayspastdueandstillaccruing_019d0150-683b-703b-8b42-055cab09ee10" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.cat.com/role/CatFinancialFinancingActivitiesModificationsDetails" xlink:type="simple" xlink:href="cat-20260331.xsd#CatFinancialFinancingActivitiesModificationsDetails"/>
  <link:definitionLink xlink:role="http://www.cat.com/role/CatFinancialFinancingActivitiesModificationsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableModificationsLineItems_019d0150-683b-7804-8896-328359665d80" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancingReceivableModificationsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfFinancingReceivableTroubledDebtRestructuringsTable_019d0150-683b-70ab-b083-dc9c4fc720e7" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfFinancingReceivableTroubledDebtRestructuringsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FinancingReceivableModificationsLineItems_019d0150-683b-7804-8896-328359665d80" xlink:to="loc_us-gaap_ScheduleOfFinancingReceivableTroubledDebtRestructuringsTable_019d0150-683b-70ab-b083-dc9c4fc720e7" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablesPeriodPastDueAxis_019d0150-683b-70e8-a8f9-c6fa9a4b1019" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancingReceivablesPeriodPastDueAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivableTroubledDebtRestructuringsTable_019d0150-683b-70ab-b083-dc9c4fc720e7" xlink:to="loc_us-gaap_FinancingReceivablesPeriodPastDueAxis_019d0150-683b-70e8-a8f9-c6fa9a4b1019" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablesPeriodPastDueDomain_019d0150-683b-70e8-a8f9-c6fa9a4b1019_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancingReceivablesPeriodPastDueDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivablesPeriodPastDueAxis_019d0150-683b-70e8-a8f9-c6fa9a4b1019" xlink:to="loc_us-gaap_FinancingReceivablesPeriodPastDueDomain_019d0150-683b-70e8-a8f9-c6fa9a4b1019_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablesPeriodPastDueDomain_019d0150-683b-7fad-8556-db406e0bd3ad" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancingReceivablesPeriodPastDueDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivablesPeriodPastDueAxis_019d0150-683b-70e8-a8f9-c6fa9a4b1019" xlink:to="loc_us-gaap_FinancingReceivablesPeriodPastDueDomain_019d0150-683b-7fad-8556-db406e0bd3ad" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_FinancingReceivables31to60DaysPastDueMember_019d0150-683b-747c-973a-1e6ae22423e4" xlink:href="cat-20260331.xsd#cat_FinancingReceivables31to60DaysPastDueMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablesPeriodPastDueDomain_019d0150-683b-7fad-8556-db406e0bd3ad" xlink:to="loc_cat_FinancingReceivables31to60DaysPastDueMember_019d0150-683b-747c-973a-1e6ae22423e4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_019d0150-683b-749b-9dfd-d32eb71d8c58" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancingReceivablePortfolioSegmentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivableTroubledDebtRestructuringsTable_019d0150-683b-70ab-b083-dc9c4fc720e7" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_019d0150-683b-749b-9dfd-d32eb71d8c58" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019d0150-683b-749b-9dfd-d32eb71d8c58_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_019d0150-683b-749b-9dfd-d32eb71d8c58" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019d0150-683b-749b-9dfd-d32eb71d8c58_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019d0150-683b-7868-9f46-d1cac72812cb" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_019d0150-683b-749b-9dfd-d32eb71d8c58" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019d0150-683b-7868-9f46-d1cac72812cb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_DealerMember_019d0150-683b-75fa-bb07-66e059dbca72" xlink:href="cat-20260331.xsd#cat_DealerMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019d0150-683b-7868-9f46-d1cac72812cb" xlink:to="loc_cat_DealerMember_019d0150-683b-75fa-bb07-66e059dbca72" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_CustomerMember_019d0150-683b-775d-89ae-277fbc7cc2a4" xlink:href="cat-20260331.xsd#cat_CustomerMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019d0150-683b-7868-9f46-d1cac72812cb" xlink:to="loc_cat_CustomerMember_019d0150-683b-775d-89ae-277fbc7cc2a4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EMEAMember_019d0150-683b-77d8-82ad-d998d1aa27ed" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EMEAMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019d0150-683b-7868-9f46-d1cac72812cb" xlink:to="loc_us-gaap_EMEAMember_019d0150-683b-77d8-82ad-d998d1aa27ed" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_AsiaPacificMember_019d0150-683b-745d-ad8a-0240215a72b8" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_AsiaPacificMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019d0150-683b-7868-9f46-d1cac72812cb" xlink:to="loc_srt_AsiaPacificMember_019d0150-683b-745d-ad8a-0240215a72b8" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_NorthAmericaMember_019d0150-683b-7702-a8fd-1b2e30420ede" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_NorthAmericaMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019d0150-683b-7868-9f46-d1cac72812cb" xlink:to="loc_srt_NorthAmericaMember_019d0150-683b-7702-a8fd-1b2e30420ede" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LoanRestructuringModificationAxis_019d0150-683b-7373-bedd-ff66c564bfa0" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LoanRestructuringModificationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivableTroubledDebtRestructuringsTable_019d0150-683b-70ab-b083-dc9c4fc720e7" xlink:to="loc_us-gaap_LoanRestructuringModificationAxis_019d0150-683b-7373-bedd-ff66c564bfa0" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LoanRestructuringModificationDomain_019d0150-683b-7373-bedd-ff66c564bfa0_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LoanRestructuringModificationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LoanRestructuringModificationAxis_019d0150-683b-7373-bedd-ff66c564bfa0" xlink:to="loc_us-gaap_LoanRestructuringModificationDomain_019d0150-683b-7373-bedd-ff66c564bfa0_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LoanRestructuringModificationDomain_019d0150-683b-71cd-8124-a158eb0e3acf" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LoanRestructuringModificationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LoanRestructuringModificationAxis_019d0150-683b-7373-bedd-ff66c564bfa0" xlink:to="loc_us-gaap_LoanRestructuringModificationDomain_019d0150-683b-71cd-8124-a158eb0e3acf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentDeferralMember_019d0150-683b-7c36-99ba-29a02a04d671" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PaymentDeferralMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LoanRestructuringModificationDomain_019d0150-683b-71cd-8124-a158eb0e3acf" xlink:to="loc_us-gaap_PaymentDeferralMember_019d0150-683b-7c36-99ba-29a02a04d671" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ExtendedMaturityMember_019d0150-683b-7c24-83a2-c2b2513852c5" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ExtendedMaturityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LoanRestructuringModificationDomain_019d0150-683b-71cd-8124-a158eb0e3acf" xlink:to="loc_us-gaap_ExtendedMaturityMember_019d0150-683b-7c24-83a2-c2b2513852c5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_FinancingReceivableModifiedBorrowersNotExperiencingFinancialDifficultyMaximumPeriod_019d0150-683b-7145-8f0b-6092ba0f548b" xlink:href="cat-20260331.xsd#cat_FinancingReceivableModifiedBorrowersNotExperiencingFinancialDifficultyMaximumPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableModificationsLineItems_019d0150-683b-7804-8896-328359665d80" xlink:to="loc_cat_FinancingReceivableModifiedBorrowersNotExperiencingFinancialDifficultyMaximumPeriod_019d0150-683b-7145-8f0b-6092ba0f548b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2_019d0150-683b-74fb-a354-371a7faa34fb" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableModificationsLineItems_019d0150-683b-7804-8896-328359665d80" xlink:to="loc_us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2_019d0150-683b-74fb-a354-371a7faa34fb" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.cat.com/role/CatFinancialFinancingActivitiesFinancingReceivableModifiedDetails" xlink:type="simple" xlink:href="cat-20260331.xsd#CatFinancialFinancingActivitiesFinancingReceivableModifiedDetails"/>
  <link:definitionLink xlink:role="http://www.cat.com/role/CatFinancialFinancingActivitiesFinancingReceivableModifiedDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems_019d0150-683b-7aa6-9773-14825a781f92" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfFinancingReceivableAllowanceForCreditLossesTable_019d0150-683b-7507-a45f-936bcaa74a50" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfFinancingReceivableAllowanceForCreditLossesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems_019d0150-683b-7aa6-9773-14825a781f92" xlink:to="loc_us-gaap_ScheduleOfFinancingReceivableAllowanceForCreditLossesTable_019d0150-683b-7507-a45f-936bcaa74a50" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_019d0150-683b-76f7-8cc6-416bee2d4503" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancingReceivablePortfolioSegmentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivableAllowanceForCreditLossesTable_019d0150-683b-7507-a45f-936bcaa74a50" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_019d0150-683b-76f7-8cc6-416bee2d4503" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019d0150-683b-76f7-8cc6-416bee2d4503_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_019d0150-683b-76f7-8cc6-416bee2d4503" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019d0150-683b-76f7-8cc6-416bee2d4503_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019d0150-683b-7db2-b6b7-eb196227ec5f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_019d0150-683b-76f7-8cc6-416bee2d4503" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019d0150-683b-7db2-b6b7-eb196227ec5f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_CustomerMember_019d0150-683b-7915-b847-6a67dacd7054" xlink:href="cat-20260331.xsd#cat_CustomerMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_019d0150-683b-7db2-b6b7-eb196227ec5f" xlink:to="loc_cat_CustomerMember_019d0150-683b-7915-b847-6a67dacd7054" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LoanRestructuringModificationAxis_019d0150-683b-7e9d-93ef-265bd3747a31" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LoanRestructuringModificationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivableAllowanceForCreditLossesTable_019d0150-683b-7507-a45f-936bcaa74a50" xlink:to="loc_us-gaap_LoanRestructuringModificationAxis_019d0150-683b-7e9d-93ef-265bd3747a31" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LoanRestructuringModificationDomain_019d0150-683b-7e9d-93ef-265bd3747a31_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LoanRestructuringModificationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LoanRestructuringModificationAxis_019d0150-683b-7e9d-93ef-265bd3747a31" xlink:to="loc_us-gaap_LoanRestructuringModificationDomain_019d0150-683b-7e9d-93ef-265bd3747a31_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LoanRestructuringModificationDomain_019d0150-683b-7d76-872b-6f92194be1f7" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LoanRestructuringModificationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LoanRestructuringModificationAxis_019d0150-683b-7e9d-93ef-265bd3747a31" xlink:to="loc_us-gaap_LoanRestructuringModificationDomain_019d0150-683b-7d76-872b-6f92194be1f7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ExtendedMaturityMember_019d0150-683b-7020-8731-3e5346480b74" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ExtendedMaturityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LoanRestructuringModificationDomain_019d0150-683b-7d76-872b-6f92194be1f7" xlink:to="loc_us-gaap_ExtendedMaturityMember_019d0150-683b-7020-8731-3e5346480b74" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentDeferralMember_019d0150-683b-7fc2-9fa2-d03d86e81b0c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PaymentDeferralMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LoanRestructuringModificationDomain_019d0150-683b-7d76-872b-6f92194be1f7" xlink:to="loc_us-gaap_PaymentDeferralMember_019d0150-683b-7fc2-9fa2-d03d86e81b0c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2_019d0150-683b-7441-aa87-9752f91a4828" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems_019d0150-683b-7aa6-9773-14825a781f92" xlink:to="loc_us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2_019d0150-683b-7441-aa87-9752f91a4828" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableModificationToTotalFinancingReceivablesPercent_019d0150-683b-74bd-aa95-3e6dc5d74a5a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancingReceivableModificationToTotalFinancingReceivablesPercent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems_019d0150-683b-7aa6-9773-14825a781f92" xlink:to="loc_us-gaap_FinancingReceivableModificationToTotalFinancingReceivablesPercent_019d0150-683b-74bd-aa95-3e6dc5d74a5a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableModifiedWeightedAverageTermIncreaseFromModification_019d0150-683b-70a1-b7a9-a4eca8bb34c7" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancingReceivableModifiedWeightedAverageTermIncreaseFromModification"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems_019d0150-683b-7aa6-9773-14825a781f92" xlink:to="loc_us-gaap_FinancingReceivableModifiedWeightedAverageTermIncreaseFromModification_019d0150-683b-70a1-b7a9-a4eca8bb34c7" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.cat.com/role/FairValueDisclosuresAssetsAndLiabilitiesMeasuredOnARecurringBasisDetails" xlink:type="simple" xlink:href="cat-20260331.xsd#FairValueDisclosuresAssetsAndLiabilitiesMeasuredOnARecurringBasisDetails"/>
  <link:definitionLink xlink:role="http://www.cat.com/role/FairValueDisclosuresAssetsAndLiabilitiesMeasuredOnARecurringBasisDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_019d0150-683b-7de1-9559-12b58d0a561b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_019d0150-683b-7c0b-9938-ae62fc8f757d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_019d0150-683b-7de1-9559-12b58d0a561b" xlink:to="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_019d0150-683b-7c0b-9938-ae62fc8f757d" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_019d0150-683b-7b75-8bc9-9c6321b2cfe0" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_019d0150-683b-7c0b-9938-ae62fc8f757d" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_019d0150-683b-7b75-8bc9-9c6321b2cfe0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019d0150-683b-7b75-8bc9-9c6321b2cfe0_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_019d0150-683b-7b75-8bc9-9c6321b2cfe0" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019d0150-683b-7b75-8bc9-9c6321b2cfe0_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019d0150-683b-72d7-93bd-314529a1a05b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_019d0150-683b-7b75-8bc9-9c6321b2cfe0" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019d0150-683b-72d7-93bd-314529a1a05b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel1Member_019d0150-683b-7ef5-810e-1597225c11d7" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueInputsLevel1Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019d0150-683b-72d7-93bd-314529a1a05b" xlink:to="loc_us-gaap_FairValueInputsLevel1Member_019d0150-683b-7ef5-810e-1597225c11d7" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel2Member_019d0150-683b-7dcc-a9e6-6471e9e0d89b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueInputsLevel2Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019d0150-683b-72d7-93bd-314529a1a05b" xlink:to="loc_us-gaap_FairValueInputsLevel2Member_019d0150-683b-7dcc-a9e6-6471e9e0d89b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel3Member_019d0150-683b-704a-84f2-16ca2dcd11b6" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueInputsLevel3Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019d0150-683b-72d7-93bd-314529a1a05b" xlink:to="loc_us-gaap_FairValueInputsLevel3Member_019d0150-683b-704a-84f2-16ca2dcd11b6" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasuredAtNetAssetValuePerShareMember_019d0150-683b-70d3-9540-360df67ab732" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueMeasuredAtNetAssetValuePerShareMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019d0150-683b-72d7-93bd-314529a1a05b" xlink:to="loc_us-gaap_FairValueMeasuredAtNetAssetValuePerShareMember_019d0150-683b-70d3-9540-360df67ab732" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentAxis_019d0150-683b-7d41-a104-d7ca2551f463" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancialInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_019d0150-683b-7c0b-9938-ae62fc8f757d" xlink:to="loc_us-gaap_FinancialInstrumentAxis_019d0150-683b-7d41-a104-d7ca2551f463" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019d0150-683b-7d41-a104-d7ca2551f463_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentAxis_019d0150-683b-7d41-a104-d7ca2551f463" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019d0150-683b-7d41-a104-d7ca2551f463_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019d0150-683b-7fcc-9f88-7a18d1d1a21b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentAxis_019d0150-683b-7d41-a104-d7ca2551f463" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019d0150-683b-7fcc-9f88-7a18d1d1a21b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_USTreasurySecuritiesMember_019d0150-683b-7a8e-896c-2c9d292c7804" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_USTreasurySecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019d0150-683b-7fcc-9f88-7a18d1d1a21b" xlink:to="loc_us-gaap_USTreasurySecuritiesMember_019d0150-683b-7a8e-896c-2c9d292c7804" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_OtherUSGovernmentAndNonUSGovernmentDebtMember_019d0150-683b-76f8-9a14-3bbddf7b9964" xlink:href="cat-20260331.xsd#cat_OtherUSGovernmentAndNonUSGovernmentDebtMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019d0150-683b-7fcc-9f88-7a18d1d1a21b" xlink:to="loc_cat_OtherUSGovernmentAndNonUSGovernmentDebtMember_019d0150-683b-76f8-9a14-3bbddf7b9964" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CorporateBondSecuritiesMember_019d0150-683b-7095-84ba-a6346268f4f5" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CorporateBondSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019d0150-683b-7fcc-9f88-7a18d1d1a21b" xlink:to="loc_us-gaap_CorporateBondSecuritiesMember_019d0150-683b-7095-84ba-a6346268f4f5" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetBackedSecuritiesMember_019d0150-683b-734b-a1df-7e420dc87900" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AssetBackedSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019d0150-683b-7fcc-9f88-7a18d1d1a21b" xlink:to="loc_us-gaap_AssetBackedSecuritiesMember_019d0150-683b-734b-a1df-7e420dc87900" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_USGovernmentAgenciesDebtSecuritiesMember_019d0150-683b-7ebf-a5d4-7a84b4402c79" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_USGovernmentAgenciesDebtSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019d0150-683b-7fcc-9f88-7a18d1d1a21b" xlink:to="loc_us-gaap_USGovernmentAgenciesDebtSecuritiesMember_019d0150-683b-7ebf-a5d4-7a84b4402c79" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ResidentialMortgageBackedSecuritiesMember_019d0150-683b-7075-a2f7-5ca3dfacaf20" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ResidentialMortgageBackedSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019d0150-683b-7fcc-9f88-7a18d1d1a21b" xlink:to="loc_us-gaap_ResidentialMortgageBackedSecuritiesMember_019d0150-683b-7075-a2f7-5ca3dfacaf20" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialMortgageBackedSecuritiesMember_019d0150-683b-78de-9f5c-04e5c3229df6" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CommercialMortgageBackedSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019d0150-683b-7fcc-9f88-7a18d1d1a21b" xlink:to="loc_us-gaap_CommercialMortgageBackedSecuritiesMember_019d0150-683b-78de-9f5c-04e5c3229df6" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_LargeCapitalizationMember_019d0150-683b-7894-83c3-e562e6553c91" xlink:href="cat-20260331.xsd#cat_LargeCapitalizationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019d0150-683b-7fcc-9f88-7a18d1d1a21b" xlink:to="loc_cat_LargeCapitalizationMember_019d0150-683b-7894-83c3-e562e6553c91" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_SmallerCompanyMember_019d0150-683b-76da-81c0-8f90d8091372" xlink:href="cat-20260331.xsd#cat_SmallerCompanyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019d0150-683b-7fcc-9f88-7a18d1d1a21b" xlink:to="loc_cat_SmallerCompanyMember_019d0150-683b-76da-81c0-8f90d8091372" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_REITMember_019d0150-683b-79ec-aa8a-6a3060c1e51d" xlink:href="cat-20260331.xsd#cat_REITMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019d0150-683b-7fcc-9f88-7a18d1d1a21b" xlink:to="loc_cat_REITMember_019d0150-683b-79ec-aa8a-6a3060c1e51d" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByMeasurementFrequencyAxis_019d0150-683b-7b9d-9d59-bd6636c44350" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueByMeasurementFrequencyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_019d0150-683b-7c0b-9938-ae62fc8f757d" xlink:to="loc_us-gaap_FairValueByMeasurementFrequencyAxis_019d0150-683b-7b9d-9d59-bd6636c44350" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_019d0150-683b-7b9d-9d59-bd6636c44350_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueMeasurementFrequencyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_019d0150-683b-7b9d-9d59-bd6636c44350" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_019d0150-683b-7b9d-9d59-bd6636c44350_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_019d0150-683b-7454-8113-8d5f6520f0bf" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueMeasurementFrequencyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_019d0150-683b-7b9d-9d59-bd6636c44350" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_019d0150-683b-7454-8113-8d5f6520f0bf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsRecurringMember_019d0150-683b-75cb-89e7-d6e5a7fcfebb" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueMeasurementsRecurringMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementFrequencyDomain_019d0150-683b-7454-8113-8d5f6520f0bf" xlink:to="loc_us-gaap_FairValueMeasurementsRecurringMember_019d0150-683b-75cb-89e7-d6e5a7fcfebb" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsNonrecurringMember_019d0150-683b-7201-9d55-20f706d244db" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueMeasurementsNonrecurringMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementFrequencyDomain_019d0150-683b-7454-8113-8d5f6520f0bf" xlink:to="loc_us-gaap_FairValueMeasurementsNonrecurringMember_019d0150-683b-7201-9d55-20f706d244db" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_019d0150-683b-7c8c-9d75-9e46e0d11d65" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeInstrumentRiskAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_019d0150-683b-7c0b-9938-ae62fc8f757d" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_019d0150-683b-7c8c-9d75-9e46e0d11d65" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_019d0150-683b-7c8c-9d75-9e46e0d11d65_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_019d0150-683b-7c8c-9d75-9e46e0d11d65" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_019d0150-683b-7c8c-9d75-9e46e0d11d65_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_019d0150-683b-7913-9ec0-567bea51e0ea" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_019d0150-683b-7c8c-9d75-9e46e0d11d65" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_019d0150-683b-7913-9ec0-567bea51e0ea" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ForeignExchangeContractMember_019d0150-683b-7077-992f-d117aebdb22c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ForeignExchangeContractMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_019d0150-683b-7913-9ec0-567bea51e0ea" xlink:to="loc_us-gaap_ForeignExchangeContractMember_019d0150-683b-7077-992f-d117aebdb22c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommodityContractMember_019d0150-683b-72a5-bd3d-dcb5a7d2313f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CommodityContractMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_019d0150-683b-7913-9ec0-567bea51e0ea" xlink:to="loc_us-gaap_CommodityContractMember_019d0150-683b-72a5-bd3d-dcb5a7d2313f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestRateContractMember_019d0150-683b-793d-9408-8318cee74906" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_InterestRateContractMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_019d0150-683b-7913-9ec0-567bea51e0ea" xlink:to="loc_us-gaap_InterestRateContractMember_019d0150-683b-793d-9408-8318cee74906" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TotalReturnSwapMember_019d0150-683b-79bc-be3f-311a6384a886" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_TotalReturnSwapMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_019d0150-683b-7913-9ec0-567bea51e0ea" xlink:to="loc_us-gaap_TotalReturnSwapMember_019d0150-683b-79bc-be3f-311a6384a886" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_019d0150-683b-70c2-9e2e-5005bbb56528" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_ProductOrServiceAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_019d0150-683b-7c0b-9938-ae62fc8f757d" xlink:to="loc_srt_ProductOrServiceAxis_019d0150-683b-70c2-9e2e-5005bbb56528" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_019d0150-683b-70c2-9e2e-5005bbb56528_default" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_019d0150-683b-70c2-9e2e-5005bbb56528" xlink:to="loc_srt_ProductsAndServicesDomain_019d0150-683b-70c2-9e2e-5005bbb56528_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_019d0150-683b-777e-8e2c-0a6aa9ef44ec" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_019d0150-683b-70c2-9e2e-5005bbb56528" xlink:to="loc_srt_ProductsAndServicesDomain_019d0150-683b-777e-8e2c-0a6aa9ef44ec" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_FinancialProductsMember_019d0150-683b-7623-9c4a-62397a279094" xlink:href="cat-20260331.xsd#cat_FinancialProductsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_019d0150-683b-777e-8e2c-0a6aa9ef44ec" xlink:to="loc_cat_FinancialProductsMember_019d0150-683b-7623-9c4a-62397a279094" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtSecurities_019d0150-683b-7e41-9ebe-b8c8ad03bcef" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AvailableForSaleSecuritiesDebtSecurities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_019d0150-683b-7de1-9559-12b58d0a561b" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtSecurities_019d0150-683b-7e41-9ebe-b8c8ad03bcef" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquitySecuritiesFvNi_019d0150-683b-7514-bcf3-cc964fca0bdf" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EquitySecuritiesFvNi"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_019d0150-683b-7de1-9559-12b58d0a561b" xlink:to="loc_us-gaap_EquitySecuritiesFvNi_019d0150-683b-7514-bcf3-cc964fca0bdf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeAssetsLiabilitiesAtFairValueNet_019d0150-683b-75bc-b625-91b3883e277b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeAssetsLiabilitiesAtFairValueNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_019d0150-683b-7de1-9559-12b58d0a561b" xlink:to="loc_us-gaap_DerivativeAssetsLiabilitiesAtFairValueNet_019d0150-683b-75bc-b625-91b3883e277b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsFairValueDisclosure_019d0150-683b-79e6-b756-63f55c22991f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AssetsFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_019d0150-683b-7de1-9559-12b58d0a561b" xlink:to="loc_us-gaap_AssetsFairValueDisclosure_019d0150-683b-79e6-b756-63f55c22991f" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesFairValueDisclosure_019d0150-683b-7cb0-8324-d9eef4c351f6" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LiabilitiesFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_019d0150-683b-7de1-9559-12b58d0a561b" xlink:to="loc_us-gaap_LiabilitiesFairValueDisclosure_019d0150-683b-7cb0-8324-d9eef4c351f6" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_LoansCarriedAtFairValue_019d0150-683b-736c-add5-d8f6dd13e140" xlink:href="cat-20260331.xsd#cat_LoansCarriedAtFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_019d0150-683b-7de1-9559-12b58d0a561b" xlink:to="loc_cat_LoansCarriedAtFairValue_019d0150-683b-736c-add5-d8f6dd13e140" xlink:type="arc" order="5"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.cat.com/role/FairValueDisclosuresFairValueOfFinancialInstrumentsDetails" xlink:type="simple" xlink:href="cat-20260331.xsd#FairValueDisclosuresFairValueOfFinancialInstrumentsDetails"/>
  <link:definitionLink xlink:role="http://www.cat.com/role/FairValueDisclosuresFairValueOfFinancialInstrumentsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_019d0150-683b-7717-ac16-d5e1a1724c15" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByBalanceSheetGroupingTable_019d0150-683b-7335-aec0-8bf7b97a8147" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueByBalanceSheetGroupingTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_019d0150-683b-7717-ac16-d5e1a1724c15" xlink:to="loc_us-gaap_FairValueByBalanceSheetGroupingTable_019d0150-683b-7335-aec0-8bf7b97a8147" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_019d0150-683b-7d1e-b9ea-f32e0a4a2cfe" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueByBalanceSheetGroupingTable_019d0150-683b-7335-aec0-8bf7b97a8147" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_019d0150-683b-7d1e-b9ea-f32e0a4a2cfe" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019d0150-683b-7d1e-b9ea-f32e0a4a2cfe_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_019d0150-683b-7d1e-b9ea-f32e0a4a2cfe" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019d0150-683b-7d1e-b9ea-f32e0a4a2cfe_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019d0150-683b-787d-ad7f-158b1a66d6a5" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_019d0150-683b-7d1e-b9ea-f32e0a4a2cfe" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019d0150-683b-787d-ad7f-158b1a66d6a5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel3Member_019d0150-683b-7a79-bb3f-87c2a56ecf88" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueInputsLevel3Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019d0150-683b-787d-ad7f-158b1a66d6a5" xlink:to="loc_us-gaap_FairValueInputsLevel3Member_019d0150-683b-7a79-bb3f-87c2a56ecf88" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel2Member_019d0150-683b-7803-aab4-793c01715f64" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueInputsLevel2Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019d0150-683b-787d-ad7f-158b1a66d6a5" xlink:to="loc_us-gaap_FairValueInputsLevel2Member_019d0150-683b-7803-aab4-793c01715f64" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByMeasurementBasisAxis_019d0150-683b-776d-9b45-b7df2b3eab62" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueByMeasurementBasisAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueByBalanceSheetGroupingTable_019d0150-683b-7335-aec0-8bf7b97a8147" xlink:to="loc_us-gaap_FairValueByMeasurementBasisAxis_019d0150-683b-776d-9b45-b7df2b3eab62" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_019d0150-683b-776d-9b45-b7df2b3eab62_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PortionAtFairValueFairValueDisclosureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByMeasurementBasisAxis_019d0150-683b-776d-9b45-b7df2b3eab62" xlink:to="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_019d0150-683b-776d-9b45-b7df2b3eab62_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueDisclosureItemAmountsDomain_019d0150-683b-7b96-998e-4ddf752a23c1" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueDisclosureItemAmountsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByMeasurementBasisAxis_019d0150-683b-776d-9b45-b7df2b3eab62" xlink:to="loc_us-gaap_FairValueDisclosureItemAmountsDomain_019d0150-683b-7b96-998e-4ddf752a23c1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_019d0150-683b-71a7-bdee-499e3fb739e4" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PortionAtFairValueFairValueDisclosureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueDisclosureItemAmountsDomain_019d0150-683b-7b96-998e-4ddf752a23c1" xlink:to="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_019d0150-683b-71a7-bdee-499e3fb739e4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CarryingReportedAmountFairValueDisclosureMember_019d0150-683b-7309-bbee-dee17e797737" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CarryingReportedAmountFairValueDisclosureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueDisclosureItemAmountsDomain_019d0150-683b-7b96-998e-4ddf752a23c1" xlink:to="loc_us-gaap_CarryingReportedAmountFairValueDisclosureMember_019d0150-683b-7309-bbee-dee17e797737" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EstimateOfFairValueFairValueDisclosureMember_019d0150-683b-7cb6-9b7f-1409078779e0" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EstimateOfFairValueFairValueDisclosureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueDisclosureItemAmountsDomain_019d0150-683b-7b96-998e-4ddf752a23c1" xlink:to="loc_us-gaap_EstimateOfFairValueFairValueDisclosureMember_019d0150-683b-7cb6-9b7f-1409078779e0" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PortionAtOtherThanFairValueFairValueDisclosureMember_019d0150-683b-7ee6-9c56-b2f7ea66aa06" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PortionAtOtherThanFairValueFairValueDisclosureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueDisclosureItemAmountsDomain_019d0150-683b-7b96-998e-4ddf752a23c1" xlink:to="loc_us-gaap_PortionAtOtherThanFairValueFairValueDisclosureMember_019d0150-683b-7ee6-9c56-b2f7ea66aa06" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_019d0150-683b-738f-ab80-22fa9fc0ba4b" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_ProductOrServiceAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueByBalanceSheetGroupingTable_019d0150-683b-7335-aec0-8bf7b97a8147" xlink:to="loc_srt_ProductOrServiceAxis_019d0150-683b-738f-ab80-22fa9fc0ba4b" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_019d0150-683b-738f-ab80-22fa9fc0ba4b_default" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_019d0150-683b-738f-ab80-22fa9fc0ba4b" xlink:to="loc_srt_ProductsAndServicesDomain_019d0150-683b-738f-ab80-22fa9fc0ba4b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_019d0150-683b-71ac-a6dd-ed904d472e5f" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_019d0150-683b-738f-ab80-22fa9fc0ba4b" xlink:to="loc_srt_ProductsAndServicesDomain_019d0150-683b-71ac-a6dd-ed904d472e5f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_MachineryPowerEnergyMember_019d0150-683b-71b8-9cee-ba3d02bacd8b" xlink:href="cat-20260331.xsd#cat_MachineryPowerEnergyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_019d0150-683b-71ac-a6dd-ed904d472e5f" xlink:to="loc_cat_MachineryPowerEnergyMember_019d0150-683b-71b8-9cee-ba3d02bacd8b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_FinancialProductsMember_019d0150-683b-7c1e-9dad-d6a6e1d53ee7" xlink:href="cat-20260331.xsd#cat_FinancialProductsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_019d0150-683b-71ac-a6dd-ed904d472e5f" xlink:to="loc_cat_FinancialProductsMember_019d0150-683b-7c1e-9dad-d6a6e1d53ee7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByMeasurementFrequencyAxis_019d0150-683b-7a6a-b397-fe87d873fbb6" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueByMeasurementFrequencyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueByBalanceSheetGroupingTable_019d0150-683b-7335-aec0-8bf7b97a8147" xlink:to="loc_us-gaap_FairValueByMeasurementFrequencyAxis_019d0150-683b-7a6a-b397-fe87d873fbb6" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_019d0150-683b-7a6a-b397-fe87d873fbb6_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueMeasurementFrequencyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_019d0150-683b-7a6a-b397-fe87d873fbb6" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_019d0150-683b-7a6a-b397-fe87d873fbb6_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_019d0150-683b-7ad6-90a0-b9f744ce9393" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueMeasurementFrequencyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_019d0150-683b-7a6a-b397-fe87d873fbb6" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_019d0150-683b-7ad6-90a0-b9f744ce9393" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsNonrecurringMember_019d0150-683b-7b55-9bdb-a3d3ff64edfd" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueMeasurementsNonrecurringMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementFrequencyDomain_019d0150-683b-7ad6-90a0-b9f744ce9393" xlink:to="loc_us-gaap_FairValueMeasurementsNonrecurringMember_019d0150-683b-7b55-9bdb-a3d3ff64edfd" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentsFinancialAssetsBalanceSheetGroupingsAbstract_019d0150-683b-7a48-bf2b-bdc0c651b9ba" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancialInstrumentsFinancialAssetsBalanceSheetGroupingsAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_019d0150-683b-7717-ac16-d5e1a1724c15" xlink:to="loc_us-gaap_FinancialInstrumentsFinancialAssetsBalanceSheetGroupingsAbstract_019d0150-683b-7a48-bf2b-bdc0c651b9ba" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_FinanceReceivablesNet_019d0150-683b-7a3a-b2ba-0112ae6e3d84" xlink:href="cat-20260331.xsd#cat_FinanceReceivablesNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancialInstrumentsFinancialAssetsBalanceSheetGroupingsAbstract_019d0150-683b-7a48-bf2b-bdc0c651b9ba" xlink:to="loc_cat_FinanceReceivablesNet_019d0150-683b-7a3a-b2ba-0112ae6e3d84" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_WholesaleInventoryReceivables_019d0150-683b-7503-9091-713770033d3d" xlink:href="cat-20260331.xsd#cat_WholesaleInventoryReceivables"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancialInstrumentsFinancialAssetsBalanceSheetGroupingsAbstract_019d0150-683b-7a48-bf2b-bdc0c651b9ba" xlink:to="loc_cat_WholesaleInventoryReceivables_019d0150-683b-7503-9091-713770033d3d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_FinanceleasesandfailedsaleleasebacksCarryingValue_019d0150-683b-7fd3-86e5-224278882b8d" xlink:href="cat-20260331.xsd#cat_FinanceleasesandfailedsaleleasebacksCarryingValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancialInstrumentsFinancialAssetsBalanceSheetGroupingsAbstract_019d0150-683b-7a48-bf2b-bdc0c651b9ba" xlink:to="loc_cat_FinanceleasesandfailedsaleleasebacksCarryingValue_019d0150-683b-7fd3-86e5-224278882b8d" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentsFinancialLiabilitiesBalanceSheetGroupingsAbstract_019d0150-683b-73d8-8871-ac37af88efa8" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancialInstrumentsFinancialLiabilitiesBalanceSheetGroupingsAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_019d0150-683b-7717-ac16-d5e1a1724c15" xlink:to="loc_us-gaap_FinancialInstrumentsFinancialLiabilitiesBalanceSheetGroupingsAbstract_019d0150-683b-73d8-8871-ac37af88efa8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtFairValue_019d0150-683b-7d41-8087-f3b7103a7c27" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LongTermDebtFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancialInstrumentsFinancialLiabilitiesBalanceSheetGroupingsAbstract_019d0150-683b-73d8-8871-ac37af88efa8" xlink:to="loc_us-gaap_LongTermDebtFairValue_019d0150-683b-7d41-8087-f3b7103a7c27" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.cat.com/role/RestructuringIncomeCostsRestructuringAndRelatedCostsDetails" xlink:type="simple" xlink:href="cat-20260331.xsd#RestructuringIncomeCostsRestructuringAndRelatedCostsDetails"/>
  <link:definitionLink xlink:role="http://www.cat.com/role/RestructuringIncomeCostsRestructuringAndRelatedCostsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringCostAndReserveLineItems_019d0150-683b-7326-a9d5-ab53c27274c8" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RestructuringCostAndReserveLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_019d0150-683b-7b06-a15a-db94ca6bc40f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfRestructuringAndRelatedCostsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RestructuringCostAndReserveLineItems_019d0150-683b-7326-a9d5-ab53c27274c8" xlink:to="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_019d0150-683b-7b06-a15a-db94ca6bc40f" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringCostAndReserveAxis_019d0150-683b-7831-92d3-42905e1f00ba" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RestructuringCostAndReserveAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_019d0150-683b-7b06-a15a-db94ca6bc40f" xlink:to="loc_us-gaap_RestructuringCostAndReserveAxis_019d0150-683b-7831-92d3-42905e1f00ba" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TypeOfRestructuringDomain_019d0150-683b-7831-92d3-42905e1f00ba_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_TypeOfRestructuringDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RestructuringCostAndReserveAxis_019d0150-683b-7831-92d3-42905e1f00ba" xlink:to="loc_us-gaap_TypeOfRestructuringDomain_019d0150-683b-7831-92d3-42905e1f00ba_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TypeOfRestructuringDomain_019d0150-683b-7d7b-b357-419ba7a51799" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_TypeOfRestructuringDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RestructuringCostAndReserveAxis_019d0150-683b-7831-92d3-42905e1f00ba" xlink:to="loc_us-gaap_TypeOfRestructuringDomain_019d0150-683b-7d7b-b357-419ba7a51799" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeSeveranceMember_019d0150-683b-743a-a4ce-11da8744fce8" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EmployeeSeveranceMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TypeOfRestructuringDomain_019d0150-683b-7d7b-b357-419ba7a51799" xlink:to="loc_us-gaap_EmployeeSeveranceMember_019d0150-683b-743a-a4ce-11da8744fce8" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherRestructuringMember_019d0150-683b-76d0-8261-eed34318ba3b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherRestructuringMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TypeOfRestructuringDomain_019d0150-683b-7d7b-b357-419ba7a51799" xlink:to="loc_us-gaap_OtherRestructuringMember_019d0150-683b-76d0-8261-eed34318ba3b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringCharges_019d0150-683b-7662-9bbb-d1b1f8a97da3" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RestructuringCharges"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestructuringCostAndReserveLineItems_019d0150-683b-7326-a9d5-ab53c27274c8" xlink:to="loc_us-gaap_RestructuringCharges_019d0150-683b-7662-9bbb-d1b1f8a97da3" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.cat.com/role/SupplierFinanceProgramsDetails" xlink:type="simple" xlink:href="cat-20260331.xsd#SupplierFinanceProgramsDetails"/>
  <link:definitionLink xlink:role="http://www.cat.com/role/SupplierFinanceProgramsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SupplierFinanceProgramLineItems_019d0150-683b-706f-bfbf-3caa403cf12f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SupplierFinanceProgramLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SupplierFinanceProgramTable_019d0150-683b-72e9-b48f-792b9ee65af1" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SupplierFinanceProgramTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SupplierFinanceProgramLineItems_019d0150-683b-706f-bfbf-3caa403cf12f" xlink:to="loc_us-gaap_SupplierFinanceProgramTable_019d0150-683b-72e9-b48f-792b9ee65af1" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_019d0150-683b-744f-a31f-41a43e300d48" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_SupplierFinanceProgramTable_019d0150-683b-72e9-b48f-792b9ee65af1" xlink:to="loc_srt_RangeAxis_019d0150-683b-744f-a31f-41a43e300d48" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_019d0150-683b-744f-a31f-41a43e300d48_default" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_019d0150-683b-744f-a31f-41a43e300d48" xlink:to="loc_srt_RangeMember_019d0150-683b-744f-a31f-41a43e300d48_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_019d0150-683b-7bdc-83b3-ce73e1dd07d1" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_019d0150-683b-744f-a31f-41a43e300d48" xlink:to="loc_srt_RangeMember_019d0150-683b-7bdc-83b3-ce73e1dd07d1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_019d0150-683b-71e0-a67b-67ac0904f620" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_019d0150-683b-7bdc-83b3-ce73e1dd07d1" xlink:to="loc_srt_MinimumMember_019d0150-683b-71e0-a67b-67ac0904f620" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_019d0150-683b-79d2-b00b-76a1ccb672e4" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_019d0150-683b-7bdc-83b3-ce73e1dd07d1" xlink:to="loc_srt_MaximumMember_019d0150-683b-79d2-b00b-76a1ccb672e4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SupplierFinanceProgramPaymentTimingPeriod_019d0150-683b-784c-a07a-22e0afc81ac1" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SupplierFinanceProgramPaymentTimingPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SupplierFinanceProgramLineItems_019d0150-683b-706f-bfbf-3caa403cf12f" xlink:to="loc_us-gaap_SupplierFinanceProgramPaymentTimingPeriod_019d0150-683b-784c-a07a-22e0afc81ac1" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SupplierFinanceProgramObligationCurrent_019d0150-683b-71df-8536-500fd827158e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SupplierFinanceProgramObligationCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SupplierFinanceProgramLineItems_019d0150-683b-706f-bfbf-3caa403cf12f" xlink:to="loc_us-gaap_SupplierFinanceProgramObligationCurrent_019d0150-683b-71df-8536-500fd827158e" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.cat.com/role/AcquisitionsDetails" xlink:type="simple" xlink:href="cat-20260331.xsd#AcquisitionsDetails"/>
  <link:definitionLink xlink:role="http://www.cat.com/role/AcquisitionsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionLineItems_019dc07e-c6fe-703e-a1c8-72a032245ef7" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessAcquisitionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_019d0150-683b-78e9-93a9-e0a6941185b4" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019dc07e-c6fe-703e-a1c8-72a032245ef7" xlink:to="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_019d0150-683b-78e9-93a9-e0a6941185b4" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_019d0150-683b-7d6d-8dc4-80e9e5e137a7" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessAcquisitionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_019d0150-683b-78e9-93a9-e0a6941185b4" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_019d0150-683b-7d6d-8dc4-80e9e5e137a7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_019d0150-683b-7d6d-8dc4-80e9e5e137a7_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_019d0150-683b-7d6d-8dc4-80e9e5e137a7" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_019d0150-683b-7d6d-8dc4-80e9e5e137a7_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_019d0150-683b-7ecb-9028-364525835a26" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_019d0150-683b-7d6d-8dc4-80e9e5e137a7" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_019d0150-683b-7ecb-9028-364525835a26" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_RPMGlobalMember_019dc045-0ca7-75a1-ba56-a07e4eb3ce97" xlink:href="cat-20260331.xsd#cat_RPMGlobalMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_019d0150-683b-7ecb-9028-364525835a26" xlink:to="loc_cat_RPMGlobalMember_019dc045-0ca7-75a1-ba56-a07e4eb3ce97" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_019dc086-27aa-7039-a81f-5dc76b2be3bd" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_019d0150-683b-78e9-93a9-e0a6941185b4" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_019dc086-27aa-7039-a81f-5dc76b2be3bd" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_019dc086-27aa-7039-a81f-5dc76b2be3bd_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_019dc086-27aa-7039-a81f-5dc76b2be3bd" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_019dc086-27aa-7039-a81f-5dc76b2be3bd_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_019dc086-27aa-70fb-b0d9-b73c5bb63968" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_019dc086-27aa-7039-a81f-5dc76b2be3bd" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_019dc086-27aa-70fb-b0d9-b73c5bb63968" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IntellectualPropertyMember_019dc086-27aa-7193-a798-42d0a0818c86" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IntellectualPropertyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_019dc086-27aa-70fb-b0d9-b73c5bb63968" xlink:to="loc_us-gaap_IntellectualPropertyMember_019dc086-27aa-7193-a798-42d0a0818c86" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CustomerRelationshipsMember_019dc086-27aa-7076-af78-800ed075ddbf" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CustomerRelationshipsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_019dc086-27aa-70fb-b0d9-b73c5bb63968" xlink:to="loc_us-gaap_CustomerRelationshipsMember_019dc086-27aa-7076-af78-800ed075ddbf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TradeNamesMember_019dc086-27aa-72d9-aef9-a6b7c81be982" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_TradeNamesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_019dc086-27aa-70fb-b0d9-b73c5bb63968" xlink:to="loc_us-gaap_TradeNamesMember_019dc086-27aa-72d9-aef9-a6b7c81be982" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired_019dc07e-c6fe-700d-a1a3-486be5080aaf" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019dc07e-c6fe-703e-a1c8-72a032245ef7" xlink:to="loc_us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired_019dc07e-c6fe-700d-a1a3-486be5080aaf" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAcquiredFromAcquisition_019dc07e-c6fe-7381-9c36-5406ad337032" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CashAcquiredFromAcquisition"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019dc07e-c6fe-703e-a1c8-72a032245ef7" xlink:to="loc_us-gaap_CashAcquiredFromAcquisition_019dc07e-c6fe-7381-9c36-5406ad337032" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cat_BusinessCombinationRecognizedIdentifiableAssetsAcquiredandLiabilitiesAssumedTangibleAssets_019dc086-27aa-72e8-bcfd-106a80bdd020" xlink:href="cat-20260331.xsd#cat_BusinessCombinationRecognizedIdentifiableAssetsAcquiredandLiabilitiesAssumedTangibleAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019dc07e-c6fe-703e-a1c8-72a032245ef7" xlink:to="loc_cat_BusinessCombinationRecognizedIdentifiableAssetsAcquiredandLiabilitiesAssumedTangibleAssets_019dc086-27aa-72e8-bcfd-106a80bdd020" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCashAndEquivalents_019dc0a4-13ee-7e0f-990d-bf7ad9e2fc13" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCashAndEquivalents"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019dc07e-c6fe-703e-a1c8-72a032245ef7" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCashAndEquivalents_019dc0a4-13ee-7e0f-990d-bf7ad9e2fc13" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsReceivables_019dc086-27aa-75d3-8b3b-2b49ae6ff4ef" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsReceivables"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019dc07e-c6fe-703e-a1c8-72a032245ef7" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsReceivables_019dc086-27aa-75d3-8b3b-2b49ae6ff4ef" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibles_019dc086-27aa-7e93-9b82-4d3eb68bae06" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibles"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019dc07e-c6fe-703e-a1c8-72a032245ef7" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibles_019dc086-27aa-7e93-9b82-4d3eb68bae06" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AcquiredFiniteLivedIntangibleAssetsWeightedAverageUsefulLife_019dc086-27aa-7205-8b64-446993239741" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AcquiredFiniteLivedIntangibleAssetsWeightedAverageUsefulLife"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019dc07e-c6fe-703e-a1c8-72a032245ef7" xlink:to="loc_us-gaap_AcquiredFiniteLivedIntangibleAssetsWeightedAverageUsefulLife_019dc086-27aa-7205-8b64-446993239741" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilities_019dc086-27aa-7768-bbc0-178fff2fed7d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019dc07e-c6fe-703e-a1c8-72a032245ef7" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilities_019dc086-27aa-7768-bbc0-178fff2fed7d" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Goodwill_019dc086-27aa-7aa2-b0e8-6c499da9c60d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_Goodwill"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019dc07e-c6fe-703e-a1c8-72a032245ef7" xlink:to="loc_us-gaap_Goodwill_019dc086-27aa-7aa2-b0e8-6c499da9c60d" xlink:type="arc" order="8"/>
  </link:definitionLink>
</link:linkbase>
