The slot is an area of a machine through which coins are inserted or cards and/or bets are placed. The term also describes the part of the machine through which symbols line up on the payline to win. The symbols on a slot machine are typically drawn in various patterns to create different combinations of wins and special game features. The number of combinations a player can make is limited by the amount of symbols that are available and how many stop on each reel.

Modern slot machines use microprocessors to weight particular symbols and make them appear more often than others. This allows manufacturers to create more winning combinations without sacrificing the jackpot size. The number of stops on each reel is also important to the odds of a machine. Originally, slot machines used mechanical reels that had only one or two stops per spin. Modern electronic slot machines can have several hundred or even thousands of possible stops on each of their multiple reels.

In the United States, slot (masculine) and slot machine (feminine), or fruit machine in British English, are a type of casino game that pays out winning combinations of symbols on a fixed number of paylines. Most states regulate the placement and number of slot machines and limit their ownership to gaming establishments. Some states, such as Alaska, Arizona, Arkansas, California, Colorado, Idaho, Montana, Nevada, and Wyoming, allow private ownership of slot machines of a certain age. Other states prohibit the possession of all slot machines, and most ban them from licensed establishments.