A slot is a narrow notch, groove, or opening, such as a keyway in machinery or a slit for a coin in a vending machine. The slots in the wings of an airplane help maintain a smooth flow of air over the surface of the wing. A slot in a wall or door allows for the passage of light. A slot in a computer memory stores information. The term also refers to a position in a sequence, series, or job; for example, “he had the slot as chief copy editor”.

A computer inside a modern slot machine uses a microprocessor to keep track of the number and location of symbols on each reel. These microprocessors allow manufacturers to assign different probabilities for each symbol on each reel. To a player, it may appear that a winning symbol was “so close,” but in reality the probability of hitting it is very low.

The history of slot machines is long and complicated. The first was invented in 1891 by New Yorkers Sittman and Pitt. Their machine used a drum with 50 poker cards in five rows and allowed players to win by lining up matching cards. It was not as reliable as today’s machines, which use microprocessors to determine the odds of a winning combination.

In aviation, a slot is an authorized time and place for a plane to take off or land at a busy airport. Using slots can reduce delays and fuel burn from too many flights waiting to land or take off at the same time. Slots are especially helpful in areas with high population density and limited runway length.