A slot is a notch or groove, especially one that accepts a coin in a vending machine. A computer has slots where expansion boards can be inserted to expand the capabilities of the system. The term is also used for the position on a football team’s defense that a player lines up in, usually between a boundary cornerback and a slot receiver.

On a slot machine, the player inserts cash or, in “ticket-in, ticket-out” machines, a paper ticket with a barcode, and then activates the machine by pressing a lever or button (either physical or on a touchscreen). The reels spin and stop to rearrange symbols and credit the player according to the pay table displayed on the machine’s face. Many slot games have a theme, and symbols vary depending on the theme. Some are themed around fruit, others around classic symbols such as bells and stylized lucky sevens.

When a slot is full, it lights up to indicate that change is needed, the player wants to hand pay or there’s a problem with the machine. A light on top of the slot machine, called a candle, also flashes to alert the operator to changes in capacity demands. In addition, a slot may contain a message for the operator to read or a credit meter. The messages are often accompanied by music or other audio, and the meter’s display is designed to match the game’s theme and user interface.