<?xml version="1.0" encoding="utf-8"?>
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  <!-- INTEGIX by Ez-XBRL -->
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    <loc xlink:type="locator" xlink:href="ck0001222719-20260904.xsd#ck0001222719_MandatoryRedeemablePreferredSharesSeriesCMember" xlink:label="loc_ck0001222719_MandatoryRedeemablePreferredSharesSeriesCMember_4"/>
    <loc xlink:type="locator" xlink:href="ck0001222719-20260904.xsd#ck0001222719_MandatoryRedeemablePreferredSharesSeriesDMember" xlink:label="loc_ck0001222719_MandatoryRedeemablePreferredSharesSeriesDMember_5"/>
    <loc xlink:type="locator" xlink:href="ck0001222719-20260904.xsd#ck0001222719_MandatoryRedeemablePreferredSharesSeriesEMember" xlink:label="loc_ck0001222719_MandatoryRedeemablePreferredSharesSeriesEMember_6"/>
    <loc xlink:type="locator" xlink:href="ck0001222719-20260904.xsd#ck0001222719_MandatoryRedeemablePreferredSharesSeriesGMember" xlink:label="loc_ck0001222719_MandatoryRedeemablePreferredSharesSeriesGMember_7"/>
    <loc xlink:type="locator" xlink:href="ck0001222719-20260904.xsd#ck0001222719_MandatoryRedeemablePreferredSharesSeriesHMember" xlink:label="loc_ck0001222719_MandatoryRedeemablePreferredSharesSeriesHMember_8"/>
    <loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_0"/>
    <loc xlink:type="locator" xlink:href="ck0001222719-20260904.xsd#ck0001222719_LoanMember" xlink:label="loc_ck0001222719_LoanMember_12"/>
    <loc xlink:type="locator" xlink:href="ck0001222719-20260904.xsd#ck0001222719_MandatoryRedeemablePreferredSharesMember" xlink:label="loc_ck0001222719_MandatoryRedeemablePreferredSharesMember_13"/>
    <loc xlink:type="locator" xlink:href="ck0001222719-20260904.xsd#ck0001222719_FacilityMember" xlink:label="loc_ck0001222719_FacilityMember_14"/>
    <loc xlink:type="locator" xlink:href="ck0001222719-20260904.xsd#ck0001222719_Notes2035Member" xlink:label="loc_ck0001222719_Notes2035Member_15"/>
    <loc xlink:type="locator" xlink:href="ck0001222719-20260904.xsd#ck0001222719_SeriesATermPreferredStockDue2025Member" xlink:label="loc_ck0001222719_SeriesATermPreferredStockDue2025Member_16"/>
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  <link:definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/cef/role/RiskOnly">
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/cef/2026/cef-2026.xsd#cef_AllRisksMember" xlink:label="loc_cef_AllRisksMember_0"/>
  </link:definitionLink>
</link:linkbase>
