What is a Slot Machine?

A hole, slit, or opening in a surface or an object. Also: a position in a group, series, or sequence; a berth; a spot. Examples:

The slot in the wing of an airplane used for a high-lift device.

In a slot machine, a player inserts cash or, in “ticket-in, ticket-out” machines, a paper ticket with a barcode, into a designated slot and activates the machine by pushing a button (physical or on a touchscreen). The reels spin, and when a winning combination of symbols is lined up, the machine pays out credits according to the payout table. Symbols vary, but classic icons include fruits, bells, and stylized lucky sevens. Most slot games have a theme, and bonus features align with that theme.

While it’s possible to win a lot of money on slot machines, they can also be very frustrating. Anyone who’s ever played a slot machine has probably noticed how some symbols don’t appear on the reels for ages, then they seem to be everywhere. This is a result of the way random number generators — the computer programs that determine the results of slot games — work.

When you play a slot machine, the RNG records each of millions of possible combinations and assigns each combination a three-number sequence. When a machine receives a signal, the RNG sets that sequence to the current reel stop, and the reels spin until they reach that combination. Between signals, the RNG runs dozens of numbers every second.