A "library card" is a special card that allows you to borrow books, magazines, movies, and other items from a library. It's like your own key to access and enjoy all the resources a library has to offer. Full definition
The digital lending company also informed attendees on its cloud - based digital borrowing platform that requires no sensitive information from users other than a valid library card number. (goodereader.com)
The library is run along normal lines, with library cards for borrowing books, and caters particularly for children. (theguardian.com)
As we walked back out into the library, I saw that a family of five had come in and lined up at the check - out counter to get library cards. (sortacrunchy.net)