1. An official government document that certifies one's identity and citizenship and permits a citizen to travel abroad.
2. An official permit issued by a foreign country allowing one to transport goods or to travel through that country.
3. An official document issued by an allied foreign government to a ship, especially a neutral merchant ship in time of war, authorizing it to enter and travel through certain waters freely.
4. Something that gives one the right or privilege of passage, entry, or acceptance: Hard work was her passport to success.

[French passeport, from Old French : passer, to pass; see pass + port, port; see port¹.]

The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.