passport
An official document normally used for international journeys, which proves the identity and nationality of the person for whom it was issued.
Example
“You will have to bring your passport to prove who you are.”
Other meanings
Something which enables someone to do or achieve something.
“The tenor's voice was his passport to the international concert circuit.”
An identification document used by firefighters, collected when they enter a dangerous area and returned when they leave, to keep track of who is still in the area.
Example sentences
Word history
From French "passeport".
Where this comes from
This definition is adapted from “passport” on Wiktionary, by its contributors; example sentences are from Tatoeba, credited to their authors above, published under CC BY-SA 4.0. This page is published under the same licence.