A slot is an opening or groove in a thing. It may also refer to:

In a casino, a slot is the area where coins are placed. A player will receive a payout if the symbols line up in a winning combination. The probability of hitting a jackpot depends on the machine type, the house edge and the price of the coin.

Modern slot machines use random number generators to determine the odds of a win. When you pull the lever or press the spin button, the random number generator selects a set of numbers that correspond to positions on the reels. The machine then sets the stops on the reels to match those numbers. The machine then pays out according to the paytable.

Charles Fey invented the first mechanical slot machine in 1887. His machine used a lever to operate and was much more user-friendly than the Sittman and Pitt invention. His machine allowed automatic payouts and had three reels with the symbols hearts, diamonds, horseshoes, and liberty bells. Three aligned liberty bells were the highest-paying symbol.

A slot is a time or place allocated for a planned operation, as authorized by an airport or air-traffic control authority. Slots are used in the United States and around the world to manage airport traffic, especially at very busy airports, and to avoid repeat delays that result from too many flights trying to take off or land at the same time. See also slat1 (def. 2), and slat2 (def. 3).