In a slot machine, players insert cash or, in “ticket-in, ticket-out” machines, a paper ticket with a barcode. The machine then activates a series of reels that spin and stop to rearrange symbols. When a matching combination of symbols forms in one or more rows, the player earns credits based on the paytable. Symbols vary with each game, but classic symbols include fruits, bells, and stylized lucky sevens. Most slots have a theme, and bonus features align with that theme.
Modern computerized slot machines look like the mechanical ones, but they work on a different principle. Instead of using gears to spin the reels, they use step motors controlled by a computer. Each step in the motor moves the reel a small amount, or increment (see Introduction to Step Motor Systems), and the computer program tells the step motors when to stop. The odds of a winning or losing spin are determined by which symbols line up on the pay line, a central line visible through a viewing window.
The term slot is also used in professional football to describe the second wide receiver on a team, usually listed just behind the outside receivers. In order to excel at the position, slot receivers must be fast and have great hands as well as a precise understanding of route running and timing. This is why many teams now rely heavily on slot receivers. They are also often shorter than traditional wide receivers and require more physical prowess.