In this chapter:

(1) "Apportionable estate" means the value of the gross estate as finally determined for purposes of the estate tax to be apportioned reduced by:

(A) any claim or expense allowable as a deduction for purposes of the tax;

(B) the value of any interest in property that, for purposes of the tax, qualifies for a marital or charitable deduction or otherwise is deductible or is exempt; and

(C) any amount added to the decedent's gross estate because of a gift tax on transfers made before death.

(2) "Estate tax" means a federal, state, or foreign tax imposed because of the death of an individual and interest and penalties associated with the tax. The term does not include an inheritance tax, income tax, or generation-skipping transfer tax other than a generation-skipping transfer tax incurred on a direct skip taking effect at death.

(3) "Gross estate" means, with respect to an estate tax, all interests in property subject to the tax.

(4) "Person" means an individual, corporation, business trust, estate, trust, partnership, limited liability company, association, joint venture, public corporation, government, governmental subdivision, agency, or instrumentality, or any other legal or commercial entity.

(5) "Ratable" means apportioned or allocated pro rata according to the relative values of interests to which the term is to be applied. "Ratably" has a corresponding meaning.

(6) "Time-limited interest" means an interest in property which terminates on a lapse of time or on the occurrence or nonoccurrence of an event or which is subject to the exercise of discretion that could transfer a beneficial interest to another person. The term does not include a cotenancy unless the cotenancy itself is a time-limited interest. The term also does not include an interest in property to the extent the beneficiary has a right to accelerate, require, or elect to receive a distribution of the property.

(7) "Value" means, with respect to an interest in property, fair market value as finally determined for purposes of the estate tax that is to be apportioned, reduced by any outstanding debt secured by the interest without reduction for taxes paid or required to be paid or for any special valuation adjustment.