For the purposes of this part:

The term alien means any person who is not a citizen or national of the United States.

The term Commissioner means the Commissioner of Immigration and Naturalization.

The term regional commissioner means an officer of the Immigration and Naturalization Service duly appointed or designated as a regional commissioner, or an officer who has been designated to act as a regional commissioner.

The term district director means an officer of the Immigration and Naturalization Service duly appointed or designated as a district director, or an officer who has been designated to act as a district director.

The term United States means the several States, the District of Columbia, the Canal Zone, Puerto Rico, the Virgin Islands, Guam, American Samoa, Swains Island, the Trust Territory of the Pacific Islands, and all other territory and waters, continental and insular, subject to the jurisdiction of the United States.

The term continental United States means the District of Columbia and the several States, except Alaska and Hawaii.

The term geographical part of the United States means (1) the continental United States, (2) Alaska, (3) Hawaii, (4) Puerto Rico, (5) the Virgin Islands, (6) Guam, (7) the Canal Zone, (8) American Samoa, (9) Swains Island, or (10) the Trust Territory of the Pacific Islands.

The term depart from the United States means depart by land, water, or air (1) from the United States for any foreign place, or (2) from one geographical part of the United States for a separate geographical part of the United States: Provided, That a trip or journey upon a public ferry, passenger vessel sailing coastwise on a fixed schedule, excursion vessel, or aircraft, having both termini in the continental United States or in any one of the other geographical parts of the United States and not touching any territory or waters under the jurisdiction or control of a foreign power, shall not be deemed a departure from the United States.

The term departure-control officer means any immigration officer as defined in the regulations of the Immigration and Naturalization Service who is designated to supervise the departure of aliens, or any officer or employee of the United States designated by the Governor of the Canal Zone, the High Commissioner of the Trust Territory of the Pacific Islands, or the governor of an outlying possession of the United States, to supervise the departure of aliens.

The term port of departure means a port in the continental United States, Alaska, Guam, Hawaii, Puerto Rico or the Virgin Islands, designated as a port of entry by the Attorney General or by the Commissioner, or in exceptional circumstances such other place as the departure-control officer may, in his discretion, designate in an individual case, or a port in American Samoa, Swains Island, the Canal Zone, or the Trust Territory of the Pacific Islands, designated as a port of entry by the chief executive officer thereof.

The term special inquiry officer shall have the meaning ascribed thereto in section 101(b)(4) of the Immigration and Nationality Act.