A position in a series or sequence, such as a time slot for meetings. Also: 1. A gap in a wing or tail surface used for high-lift or control purposes, or for smooth air flow. 2. A position in a slot machine.

In a slot machine, players insert cash or paper tickets with barcodes into a slot that activates reels that spin and rearrange symbols. The slot machine then determines if the player has won and pays credits based on a paytable. The symbols vary by game, but classics include fruits and stylized lucky sevens. Most slot games have a theme, and the symbols are aligned with that theme.

Charles Fey, a San Francisco mechanic, improved upon the earlier invention of the slot machine by Sittman and Pitt. His machine had three reels instead of five and allowed for automatic payouts. It also replaced poker symbols with diamonds, spades, horseshoes, hearts, and liberty bells; three aligned liberty bells was the highest win. Fey’s machines became more popular than his competitors’.

Slot machine manufacturers use microprocessors to weight particular symbols in a given paytable. This is done to compensate for the fact that each physical symbol occupies several stops on a multiple-reel display, even though it only appears on one reel at any given time. This method also increases the size of jackpots, since a specific combination of symbols can appear on many reels. The term “slot” is also used in aviation to refer to the amount of time a plane has available to land or take off at a busy airport.