Definition of the word check out

The expression "check out" has its roots in the context of libraries and bookstores. In these places, "checking out" refers to the process of borrowing a book or other item, which involves presenting the item to a librarian or salesperson, who verifies its availability and marks it as lent out to the patron. The phrase "check out" probably originated from the act of physically checking a borrowed item as it is being presented for return, to ensure that it has not been damaged or altered since it was last checked in. Today, "checking out" has broadened to denote the process of leaving a place, as in "I'm checking out of this store" or "I'm checking out early from work today," but its origins in libraries and bookstores remain a part of its etymology.