Green Card Definition

The well-known term for an Alien Registration Card (ARC). This plastic photo identification card is given to people who are legal permanent residents of the United States. It serves as a U.S. entry document, enabling holders to return to the United States after temporary absences, and it proves their right to work in the United States. The green card expires after a certain number of years and must be renewed -- but note that the holder's permanent residence itself doesn't expire, only the ability to prove it using the card.