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

<!--XBRL Document Created with the Workiva Platform-->
<!--Copyright 2026 Workiva-->
<!--r:019dbbf6-f70e-7d09-8e42-0857c59cc06e,g:adf6d2e8-51a1-471c-8405-19e00e4a6a69-->
<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.iplpower.com/role/CoverPage" xlink:type="simple" xlink:href="cik0000728391-20260420.xsd#CoverPage"/>
  <link:definitionLink xlink:role="http://www.iplpower.com/role/CoverPage" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityInformationLineItems_019dbbf6-f70e-7e7e-a5c1-d2ecebf67762" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityInformationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntitiesTable_019dbbf6-f70e-785a-aa71-df0114da3d91" 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_019dbbf6-f70e-7e7e-a5c1-d2ecebf67762" xlink:to="loc_dei_EntitiesTable_019dbbf6-f70e-785a-aa71-df0114da3d91" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_LegalEntityAxis_019dbbf6-f70e-7787-9fb6-97bcb99ec88c" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_LegalEntityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_dei_EntitiesTable_019dbbf6-f70e-785a-aa71-df0114da3d91" xlink:to="loc_dei_LegalEntityAxis_019dbbf6-f70e-7787-9fb6-97bcb99ec88c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_019dbbf6-f70e-7787-9fb6-97bcb99ec88c_default" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_019dbbf6-f70e-7787-9fb6-97bcb99ec88c" xlink:to="loc_dei_EntityDomain_019dbbf6-f70e-7787-9fb6-97bcb99ec88c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_019dbbf6-f70e-72c1-abba-8bd5741704f4" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_019dbbf6-f70e-7787-9fb6-97bcb99ec88c" xlink:to="loc_dei_EntityDomain_019dbbf6-f70e-72c1-abba-8bd5741704f4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityEmergingGrowthCompany_019dbbf6-f70e-7837-b052-7966c3616133" 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_019dbbf6-f70e-7e7e-a5c1-d2ecebf67762" xlink:to="loc_dei_EntityEmergingGrowthCompany_019dbbf6-f70e-7837-b052-7966c3616133" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentType_019dbbf6-f70e-76fd-a471-920285d97957" 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_019dbbf6-f70e-7e7e-a5c1-d2ecebf67762" xlink:to="loc_dei_DocumentType_019dbbf6-f70e-76fd-a471-920285d97957" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentPeriodEndDate_019dbbf6-f70e-7716-a77f-a2da952426b1" 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_019dbbf6-f70e-7e7e-a5c1-d2ecebf67762" xlink:to="loc_dei_DocumentPeriodEndDate_019dbbf6-f70e-7716-a77f-a2da952426b1" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityRegistrantName_019dbbf6-f70e-7684-9b9f-0b593255b98e" 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_019dbbf6-f70e-7e7e-a5c1-d2ecebf67762" xlink:to="loc_dei_EntityRegistrantName_019dbbf6-f70e-7684-9b9f-0b593255b98e" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityIncorporationStateCountryCode_019dbbf6-f70e-7993-a05f-d9312fe63436" 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_019dbbf6-f70e-7e7e-a5c1-d2ecebf67762" xlink:to="loc_dei_EntityIncorporationStateCountryCode_019dbbf6-f70e-7993-a05f-d9312fe63436" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityTaxIdentificationNumber_019dbbf6-f70e-7ce5-8b14-989754960d07" 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_019dbbf6-f70e-7e7e-a5c1-d2ecebf67762" xlink:to="loc_dei_EntityTaxIdentificationNumber_019dbbf6-f70e-7ce5-8b14-989754960d07" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressAddressLine1_019dbbf6-f70e-71c9-9159-6998ab55ddcd" 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_019dbbf6-f70e-7e7e-a5c1-d2ecebf67762" xlink:to="loc_dei_EntityAddressAddressLine1_019dbbf6-f70e-71c9-9159-6998ab55ddcd" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressCityOrTown_019dbbf6-f70e-70b0-b427-a7c14c9d695d" 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_019dbbf6-f70e-7e7e-a5c1-d2ecebf67762" xlink:to="loc_dei_EntityAddressCityOrTown_019dbbf6-f70e-70b0-b427-a7c14c9d695d" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressStateOrProvince_019dbbf6-f70e-7588-b884-24fa1d91f922" 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_019dbbf6-f70e-7e7e-a5c1-d2ecebf67762" xlink:to="loc_dei_EntityAddressStateOrProvince_019dbbf6-f70e-7588-b884-24fa1d91f922" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressPostalZipCode_019dbbf6-f70e-7c31-bd28-bb566b58e98c" 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_019dbbf6-f70e-7e7e-a5c1-d2ecebf67762" xlink:to="loc_dei_EntityAddressPostalZipCode_019dbbf6-f70e-7c31-bd28-bb566b58e98c" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_CityAreaCode_019dbbf6-f70e-79cf-b42e-c0ca681f6186" 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_019dbbf6-f70e-7e7e-a5c1-d2ecebf67762" xlink:to="loc_dei_CityAreaCode_019dbbf6-f70e-79cf-b42e-c0ca681f6186" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_LocalPhoneNumber_019dbbf6-f70e-7588-b286-ccca34322d57" 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_019dbbf6-f70e-7e7e-a5c1-d2ecebf67762" xlink:to="loc_dei_LocalPhoneNumber_019dbbf6-f70e-7588-b286-ccca34322d57" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_WrittenCommunications_019dbbf6-f70e-745c-9b83-a358ed52efff" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_WrittenCommunications"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019dbbf6-f70e-7e7e-a5c1-d2ecebf67762" xlink:to="loc_dei_WrittenCommunications_019dbbf6-f70e-745c-9b83-a358ed52efff" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_SolicitingMaterial_019dbbf6-f70e-725e-81e0-8f3fc4762509" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_SolicitingMaterial"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019dbbf6-f70e-7e7e-a5c1-d2ecebf67762" xlink:to="loc_dei_SolicitingMaterial_019dbbf6-f70e-725e-81e0-8f3fc4762509" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_PreCommencementTenderOffer_019dbbf6-f70e-74b5-9a9a-2b5ef1dbdffc" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_PreCommencementTenderOffer"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019dbbf6-f70e-7e7e-a5c1-d2ecebf67762" xlink:to="loc_dei_PreCommencementTenderOffer_019dbbf6-f70e-74b5-9a9a-2b5ef1dbdffc" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_PreCommencementIssuerTenderOffer_019dbbf6-f70e-7272-83c3-71cc0e7e0c63" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_PreCommencementIssuerTenderOffer"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019dbbf6-f70e-7e7e-a5c1-d2ecebf67762" xlink:to="loc_dei_PreCommencementIssuerTenderOffer_019dbbf6-f70e-7272-83c3-71cc0e7e0c63" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityCentralIndexKey_019dbbf6-f70e-7f16-87f1-821b6f13ecbe" 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_019dbbf6-f70e-7e7e-a5c1-d2ecebf67762" xlink:to="loc_dei_EntityCentralIndexKey_019dbbf6-f70e-7f16-87f1-821b6f13ecbe" xlink:type="arc" order="16"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_AmendmentFlag_019dbbf6-f70e-7476-ab58-9127cd6e1652" 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_019dbbf6-f70e-7e7e-a5c1-d2ecebf67762" xlink:to="loc_dei_AmendmentFlag_019dbbf6-f70e-7476-ab58-9127cd6e1652" xlink:type="arc" order="17"/>
  </link:definitionLink>
</link:linkbase>