A narrow notch, groove, or opening, as in a keyway in machinery or a slit for coins in a vending machine. Also: an opportunity to do something, as in a visit to a city or a time slot on a plane or train schedule.

In airport coordination, a time-limited authorization for a planned aircraft operation, given by air traffic control or similar authorities at busy airports to avoid repetitive delays caused by too many flights trying to take off or land at the same time. (Another term for this is TFR, or terminal flight restrictions.)

On a slot machine, a player inserts cash or, in the case of “ticket-in, ticket-out” machines, a paper ticket with a barcode, and activates the machine by pressing a lever or button (either physical or on a touchscreen). The reels then spin, and if the symbols match a winning combination as defined in the paytable, the player earns credits based on the amount indicated by the symbol. Classic symbols include fruit, bells, and stylized lucky sevens. Most slot games have a theme, and bonus features are aligned with that theme.

Before you play a slot machine, make sure you know all the rules and pay table details. This will help you to understand what is happening on the screen, including how much you can win and the number of active paylines. It is often posted on the game’s rules or information page, or as a list on the casino’s website or the game developer’s site.