A narrow notch, groove, or hole for receiving something, such as a keyway in machinery or a coin in a vending machine. Also: a position or time in a schedule, program, or sequence.
Originally, slot meant a narrow opening in a machine for accepting coins; it later referred to an allocated space or time for taking off or landing, as authorized by airport or air-traffic control authorities. Today, the term is more commonly used to refer to a computerized slot or to an allocation of space in a machine, such as the amount of money a player can bet on a spin.
In casinos, slots are games in which players spin reels to win prizes. The reels are usually lined with symbols, and winning combinations pay out according to the game rules. Many slots also have additional features, such as a progressive jackpot or bonus rounds.
The odds of getting a particular symbol appear frequently on the physical reels, but the number of possible outcomes is limited by the number of stops on each reel and the fact that symbols may appear at different times on multiple reels. In the 1980s, however, slot manufacturers incorporated electronics into their machines and programmed them to weight particular symbols—making it less likely that the machine would yield a losing combination.
A Random Number Generator (RNG) is a key part of any modern slot machine, ensuring that each spin stands on its own and is uninfluenced by the results of previous or accompanying spins. It also ensures that a pattern in the results is impossible. In fact, trying to spot a pattern can actually backfire, because the RNG produces so many different combinations that it is improbable that any of them will match up with the one you are looking for.