Exportation. A severance of goods from the mass of things belonging to the United States with the intention of uniting them to the mass of things belonging to some foreign country and shall include shipments to any possession of the United States. The export character of any shipment shall be determined by the intention with which it is made, and it assumes an export character only when destined for use in a foreign country or in a possession of the United States. For the purposes of this part, shipments to the Commonwealth of Puerto Rico, to the territories of the Virgin Islands, American Samoa and Guam, and to the Panama Canal Zone shall also be treated as exportations.
27 CFR § 28.11
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 meaning 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 things not enumerated which are in the same general class.