Commerce. Travel, trade, traffic, commerce, transportation, or communication among the several States, or between the District of Columbia and any State, or between any foreign country or any territory or possession and any State or the District of Columbia, or between points in the same State but through any other State or the District of Columbia or a foreign country.
27 CFR § 478.11
When used in this part and in forms prescribed under this part, where not otherwise distinctly expressed or manifestly incompatible with the intent thereof, terms shall have the meanings ascribed in this section. Words in the plural form shall include the singular, and vice versa, and words importing the masculine gender shall include the feminine. The terms includes and including do not exclude other things not enumerated which are in the same general class or are otherwise within the scope thereof.