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

<!--XBRL Document Created with the Workiva Platform-->
<!--Copyright 2026 Workiva-->
<!--r:019f9419-7e62-7057-9d5a-051dcf86532d,g:000105c2-f5c0-4f6e-9273-ec081cbdb110-->
<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.aep.com/role/DocumentandEntityInformation" xlink:type="simple" xlink:href="aep-20260730.xsd#DocumentandEntityInformation"/>
  <link:definitionLink xlink:role="http://www.aep.com/role/DocumentandEntityInformation" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityInformationLineItems_019f9419-7e62-78ca-89c0-39edd91d5be4" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityInformationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntitiesTable_019f9419-7e62-747b-9986-ca558dc2e57c" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntitiesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_dei_EntityInformationLineItems_019f9419-7e62-78ca-89c0-39edd91d5be4" xlink:to="loc_dei_EntitiesTable_019f9419-7e62-747b-9986-ca558dc2e57c" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityListingsExchangeAxis_019f9419-7e62-7de9-921e-9f21d94df994" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityListingsExchangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_dei_EntitiesTable_019f9419-7e62-747b-9986-ca558dc2e57c" xlink:to="loc_dei_EntityListingsExchangeAxis_019f9419-7e62-7de9-921e-9f21d94df994" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_ExchangeDomain_019f9419-7e62-7de9-921e-9f21d94df994_default" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_ExchangeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_EntityListingsExchangeAxis_019f9419-7e62-7de9-921e-9f21d94df994" xlink:to="loc_dei_ExchangeDomain_019f9419-7e62-7de9-921e-9f21d94df994_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_ExchangeDomain_019f9419-7e62-712f-86f8-2964efc70a75" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_ExchangeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_EntityListingsExchangeAxis_019f9419-7e62-7de9-921e-9f21d94df994" xlink:to="loc_dei_ExchangeDomain_019f9419-7e62-712f-86f8-2964efc70a75" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_exch_XNAS_019f9419-7e62-7a93-b676-96f208c40728" xlink:href="https://xbrl.sec.gov/exch/2026/exch-2026.xsd#exch_XNAS"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_ExchangeDomain_019f9419-7e62-712f-86f8-2964efc70a75" xlink:to="loc_exch_XNAS_019f9419-7e62-7a93-b676-96f208c40728" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_019f9419-7e62-73ba-b953-245cdaa58588" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_dei_EntitiesTable_019f9419-7e62-747b-9986-ca558dc2e57c" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_019f9419-7e62-73ba-b953-245cdaa58588" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_019f9419-7e62-73ba-b953-245cdaa58588_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_019f9419-7e62-73ba-b953-245cdaa58588" xlink:to="loc_us-gaap_EquityComponentDomain_019f9419-7e62-73ba-b953-245cdaa58588_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_019f9419-7e62-719a-8709-8a4a9c408551" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_019f9419-7e62-73ba-b953-245cdaa58588" xlink:to="loc_us-gaap_EquityComponentDomain_019f9419-7e62-719a-8709-8a4a9c408551" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockMember_019f9419-7e62-765b-9ae5-c7327974dd45" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_019f9419-7e62-719a-8709-8a4a9c408551" xlink:to="loc_us-gaap_CommonStockMember_019f9419-7e62-765b-9ae5-c7327974dd45" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_aep_PreferredStock2Member_019f9419-7e62-7ebc-9b2e-37cc2d92c562" xlink:href="aep-20260730.xsd#aep_PreferredStock2Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_019f9419-7e62-719a-8709-8a4a9c408551" xlink:to="loc_aep_PreferredStock2Member_019f9419-7e62-7ebc-9b2e-37cc2d92c562" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentType_019f9419-7e62-7a8e-8e6a-d4f4da6d0ee2" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_DocumentType"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019f9419-7e62-78ca-89c0-39edd91d5be4" xlink:to="loc_dei_DocumentType_019f9419-7e62-7a8e-8e6a-d4f4da6d0ee2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentPeriodEndDate_019f9419-7e62-7d0a-b63d-6eeb4fd530c1" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_DocumentPeriodEndDate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019f9419-7e62-78ca-89c0-39edd91d5be4" xlink:to="loc_dei_DocumentPeriodEndDate_019f9419-7e62-7d0a-b63d-6eeb4fd530c1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityRegistrantName_019f9419-7e62-73ab-ab0c-f82d3e71e825" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityRegistrantName"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019f9419-7e62-78ca-89c0-39edd91d5be4" xlink:to="loc_dei_EntityRegistrantName_019f9419-7e62-73ab-ab0c-f82d3e71e825" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityFileNumber_019f9419-7e62-7e02-b344-7dfe5ac569b0" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityFileNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019f9419-7e62-78ca-89c0-39edd91d5be4" xlink:to="loc_dei_EntityFileNumber_019f9419-7e62-7e02-b344-7dfe5ac569b0" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityIncorporationStateCountryCode_019f9419-7e62-7f14-bd88-7fe462ebcdeb" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityIncorporationStateCountryCode"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019f9419-7e62-78ca-89c0-39edd91d5be4" xlink:to="loc_dei_EntityIncorporationStateCountryCode_019f9419-7e62-7f14-bd88-7fe462ebcdeb" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityTaxIdentificationNumber_019f9419-7e62-7a35-a999-bd2b3325c584" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityTaxIdentificationNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019f9419-7e62-78ca-89c0-39edd91d5be4" xlink:to="loc_dei_EntityTaxIdentificationNumber_019f9419-7e62-7a35-a999-bd2b3325c584" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressAddressLine1_019f9419-7e62-7e8a-981a-e596302cc91b" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityAddressAddressLine1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019f9419-7e62-78ca-89c0-39edd91d5be4" xlink:to="loc_dei_EntityAddressAddressLine1_019f9419-7e62-7e8a-981a-e596302cc91b" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressCityOrTown_019f9419-7e62-7a6d-b1e2-9bed1fd0eb5f" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityAddressCityOrTown"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019f9419-7e62-78ca-89c0-39edd91d5be4" xlink:to="loc_dei_EntityAddressCityOrTown_019f9419-7e62-7a6d-b1e2-9bed1fd0eb5f" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressStateOrProvince_019f9419-7e62-7648-bb7b-76b2c382f57f" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityAddressStateOrProvince"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019f9419-7e62-78ca-89c0-39edd91d5be4" xlink:to="loc_dei_EntityAddressStateOrProvince_019f9419-7e62-7648-bb7b-76b2c382f57f" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressPostalZipCode_019f9419-7e62-7a03-983f-39261ce4ff9b" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityAddressPostalZipCode"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019f9419-7e62-78ca-89c0-39edd91d5be4" xlink:to="loc_dei_EntityAddressPostalZipCode_019f9419-7e62-7a03-983f-39261ce4ff9b" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_CityAreaCode_019f9419-7e62-751f-a17a-a8aaaedebf46" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_CityAreaCode"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019f9419-7e62-78ca-89c0-39edd91d5be4" xlink:to="loc_dei_CityAreaCode_019f9419-7e62-751f-a17a-a8aaaedebf46" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_LocalPhoneNumber_019f9419-7e62-73aa-bd9c-fc7cc90adad1" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_LocalPhoneNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019f9419-7e62-78ca-89c0-39edd91d5be4" xlink:to="loc_dei_LocalPhoneNumber_019f9419-7e62-73aa-bd9c-fc7cc90adad1" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_WrittenCommunications_019f9419-7e62-7499-9779-2950d822d2e9" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_WrittenCommunications"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019f9419-7e62-78ca-89c0-39edd91d5be4" xlink:to="loc_dei_WrittenCommunications_019f9419-7e62-7499-9779-2950d822d2e9" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_SolicitingMaterial_019f9419-7e62-72ad-9475-5b52b82bee85" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_SolicitingMaterial"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019f9419-7e62-78ca-89c0-39edd91d5be4" xlink:to="loc_dei_SolicitingMaterial_019f9419-7e62-72ad-9475-5b52b82bee85" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_PreCommencementTenderOffer_019f9419-7e62-7360-b7af-d01fb0236c6f" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_PreCommencementTenderOffer"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019f9419-7e62-78ca-89c0-39edd91d5be4" xlink:to="loc_dei_PreCommencementTenderOffer_019f9419-7e62-7360-b7af-d01fb0236c6f" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_PreCommencementIssuerTenderOffer_019f9419-7e62-702a-8602-97f75f6ea1c0" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_PreCommencementIssuerTenderOffer"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019f9419-7e62-78ca-89c0-39edd91d5be4" xlink:to="loc_dei_PreCommencementIssuerTenderOffer_019f9419-7e62-702a-8602-97f75f6ea1c0" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_Security12bTitle_019f9419-7e62-790d-adac-a2513f2470d3" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_Security12bTitle"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019f9419-7e62-78ca-89c0-39edd91d5be4" xlink:to="loc_dei_Security12bTitle_019f9419-7e62-790d-adac-a2513f2470d3" xlink:type="arc" order="16"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_TradingSymbol_019f9419-7e62-754d-ac04-55fe3555f73f" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_TradingSymbol"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019f9419-7e62-78ca-89c0-39edd91d5be4" xlink:to="loc_dei_TradingSymbol_019f9419-7e62-754d-ac04-55fe3555f73f" xlink:type="arc" order="17"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_SecurityExchangeName_019f9419-7e62-7114-9386-552d33f80f8f" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_SecurityExchangeName"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019f9419-7e62-78ca-89c0-39edd91d5be4" xlink:to="loc_dei_SecurityExchangeName_019f9419-7e62-7114-9386-552d33f80f8f" xlink:type="arc" order="18"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityEmergingGrowthCompany_019f9419-7e62-7c15-9f38-26f0987d85a1" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityEmergingGrowthCompany"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019f9419-7e62-78ca-89c0-39edd91d5be4" xlink:to="loc_dei_EntityEmergingGrowthCompany_019f9419-7e62-7c15-9f38-26f0987d85a1" xlink:type="arc" order="19"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityCentralIndexKey_019f9419-7e62-7a52-9588-4799e919b873" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityCentralIndexKey"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019f9419-7e62-78ca-89c0-39edd91d5be4" xlink:to="loc_dei_EntityCentralIndexKey_019f9419-7e62-7a52-9588-4799e919b873" xlink:type="arc" order="20"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_AmendmentFlag_019f9419-7e62-7043-9186-92ff059a2fb7" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_AmendmentFlag"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019f9419-7e62-78ca-89c0-39edd91d5be4" xlink:to="loc_dei_AmendmentFlag_019f9419-7e62-7043-9186-92ff059a2fb7" xlink:type="arc" order="21"/>
  </link:definitionLink>
</link:linkbase>
