A narrow opening or groove in something, often used for receiving coins or paper cards. Also called a vent, slit, aperture, vacancy, niche. He dropped a coin into the slot and dialled.

A machine that accepts cash or, in “ticket-in, ticket-out” machines, a barcoded paper ticket with a barcode to activate the reels and payout credits according to the paytable. It may feature one or multiple spinning reels with various symbols and bonus features aligned to the theme of the machine. Originally operated by lever, most modern machines are operated using buttons or touchscreens.

In scheduling, a slot is an authorization for a planned aircraft operation at an airport in a given time period. Air traffic controllers use slots to manage flight schedules at busy airports and prevent repeated delays that can occur when jobs try to take off or land at the same time.

Some people believe that a slot has a certain pattern of winning and losing, and that if it has been long since the last win, the jackpot is due any moment. This is not true, however, as the random number generator (RNG) determines results randomly. The volatility of a slot indicates how it should behave in theory – it will either pay out more frequently or less often than other slots, and it will have a different size payout. However, it is important to note that these are only theoretical indicators based on historical data.