A slot is a narrow opening in something. For example, you can put mail through a slot in a mailbox or your car seat belt slots into a hole in the buckle. The word slot also refers to a position in a queue or schedule. For instance, you may be able to book a flight with a particular airline at a specific time.

Charles Fey’s 1899 Liberty Bell machine, on display in San Francisco

In slot machines, a player inserts cash or, in ticket-in, ticket-out machines, a paper ticket with a barcode, into a slot to activate the machine and begin spinning reels that display symbols. When a winning combination appears, the machine awards credits based on the pay table. Pay tables are displayed on a screen and can include information about how to trigger bonus features, as well as the symbols that are eligible to land in a winning combination. Some modern slot games also have additional rules and mechanics that are not listed on the pay table.