library card
A Bibliothekskarte is a card that allows you to borrow books from a library. In Germany, these cards are usually issued by the library itself and are required to check out books. They may also be used to access other library services, such as online databases or study rooms.
I have forgotten my library card.
This sentence is used when someone has forgotten their library card.
You need a library card to borrow books.
This sentence is used to inform someone that a library card is required in order to borrow books from the library.
Can I see your library card?
This sentence may be used by a librarian when asking a patron to present their library card.