The terms “includes” and “including” when used in a definition contained in this title shall not be deemed to exclude other things otherwise within the meaning of the term defined. [IRC § 7701(c)]
The IRC § 7701(c) definition of “includes” is a hybrid composite of two of the principal rules of statutory construction/interpretation:
(1) expressio unius est exclusio alterius, and
(2) ejusdem generis, defined, respectively, as follows:
(1) The rule ejusdem generis (of the same kind): when a list of specific items belonging to the same class is followed by general words (as in “cats, dogs, and other animals”), the general words are to be treated as confined to other items of the same class (in this example, to other domestic animals).
(2) The rule expressio unius est exclusio alterius (the inclusion of the one is the exclusion of the other): when a list of specific items is not followed by general words it is to be taken as exhaustive. For example, “weekends and public holidays” excludes ordinary weekdays.”1
Notwithstanding that the controlling definition of “State” (IRC 7701(a)(10)) does not reveal the full extent of the associated group or series encompassed by the said definition—only that the District of Columbia is construed to be a State—the preamble to the controlling definition of “United States” and “State,” IRC § 7701(a), supra, provides instruction as to how to identify the other States, besides the District of Columbia, that
are embraced by the definition of “United States”; to wit:
When used in this title, where not otherwise distinctly expressed ... [Emphasis added.]
