In this chapter:
(1) “Estate” means the gross estate of a decedent as determined for the purpose of federal estate tax and the estate and transfer taxes payable as provided by this title;
(2) “Fiduciary” means executor, administrator of any description, and trustee;
(3) “Person” means any individual, partnership, association, joint stock company, corporation, government, political subdivision, governmental agency, or local governmental agency;
(4) “Person interested in the estate” means any person, including a personal representative, guardian, or trustee, entitled to receive, or who has received, from a decedent while alive or by reason of the death of a decedent any property or interest in property included in the decedent’s taxable estate;
(5) “State” means any state, territory, or possession of the United States, the District of Columbia, or the Commonwealth of Puerto Rico; and
(6) “Tax” means the federal estate tax and the estate and transfer taxes payable as provided by this title and interest and penalties imposed in addition to the tax.