In computers, a slot (also known as an expansion slot) is a method of adding capabilities to a computer in the form of connection pinholes that allow an expansion card containing circuitry that provides some specialized capability to be installed. Almost all desktop computers come with a set of slots that are designed to help users easily add new hardware capabilities.

Pay table

The pay table is a screen full of information that tells the player how much they can win on each spin. It also contains instructions for special features, paylines, betting requirements and any jackpots.

Credit meter

On mechanical slot machines, this is usually a seven-segment display that indicates how many credits are left. On video slot machines, it is typically a stylized text display that reflects the game’s theme.


A candle is a light on the top of a slot machine that flashes when change is needed, hand pay is requested or if there is a problem with the machine. It can be lit by the player or by an attendant.


A carousel is a group of slot machines in a circle or oval formation. It is often seen in casinos.


Each slot machine has a pay table that lists the number of credits that a player can win for matching symbols. Symbols vary depending on the game’s theme, but classic symbols include fruits, bells and stylized lucky sevens.


In the early days, some slot machines were susceptible to a scam called the top-bottom device. This worked by jamming the top of the coin slot into a metal contact to complete an electrical circuit that activated the coin dispenser. This technique was stopped by manufacturers who incorporated protection into the coin acceptors.