(1) “Credit” means the maximum credit for any estate, inheritance, legacy, or succession taxes paid to any state or territory or the District of Columbia, allowable with respect to the gross federal estate tax by § 2011 of the Internal Revenue Code of 1954 (26 U.S.C. § 2011), the maximum credit, however, to be reduced in the proportion that the amount of the nontaxable property bears to the amount of the entire estate of the decedent;

(2) “Decedent” means any person who at the time of death is a domiciliary of the state of Tennessee or who owned real estate situated within this state or tangible personal property having actual situs within this state;

(3) “Estate” means the entire estate, and/or interest in the estate, of the decedent, that is subject to or liable for the payment of the federal estate tax before deducting any losses or exemptions in accordance with the Internal Revenue Code of 1954;

(4) “Executor” includes administrator, and any other person liable for the payment of the federal estate tax;

(5) “Federal estate tax” means the tax imposed by chapter 11 of the Internal Revenue Code of 1954 (26 U.S.C. § 2001 et seq.);

(6) “Nontaxable property” means all parts of the estate or interest in the estate other than the Tennessee estate;

(7) “State taxes” means the aggregate estate, inheritance, succession, collateral inheritance and/or legacy taxes paid to any state, territory or the District of Columbia, including, also, such taxes of any of those kinds as are imposed by the state of Tennessee other than the Tennessee estate tax imposed by this part, allowable in computing the maximum credit under § 2011 of the Internal Revenue Code of 1954 (26 U.S.C. § 2011), except such taxes of any of the above kinds or with respect to nontaxable property of the decedent;

(8) “Tennessee estate” means such part of the estate, or interest in the estate, the transfer of which is within the power of the state of Tennessee to subject to the Tennessee estate tax; and

(9) “Tennessee estate tax” means the tax imposed by this part.