A slot is a narrow opening in the side of something, often used to hold a key or other item. The word is also sometimes used to refer to a position or role, such as the job of chief copy editor: “I have the slot.” In computing, it can refer to an allocation of time and space for an aircraft to take off or land, which is scheduled by airport or air-traffic authority: “Airports are trying to squeeze in more slots.”

In a casino, a slot machine is a gambling device that spins reels and pays out winning combinations based on the odds of the game. The machine accepts paper tickets with barcodes or magnetic strips, or digital representations of these tickets. Its computer system uses a random number generator (RNG) to produce a sequence of three numbers or symbols, which it then maps to positions on the digital reels. The player’s bet determines how much he or she wins.

The history of the slot machine is complex, but it is generally accepted that the first such machines were created in the 19th century by New Yorkers Sittman and Pitt. Their invention was a variation on the poker machine, with five drums and a total of 50 playing cards that could be lined up to make a winning hand. The next major development came from Charles Fey, who invented the first “best seller” – a slot machine called the Liberty Bell – in 1887.