A slot is a narrow depression, groove, notch, or slit in which something can be inserted. It may also refer to a position or job in a company or organization: “He got the slot as chief copy editor.” A slot is also the term for the opening in the primaries of certain birds that helps maintain airflow over their wings during flight.
A coin-in indicator or candle is a small light on top of a slot machine that flashes to indicate change needed, hand pay requested, machine problem or the jackpot being won. On electromechanical machines this is usually a seven-segment display, but on video slot machines it may be a stylized text display that suits the machine’s theme and user interface.
Most modern slot machines are designed to accept multiple paylines. The number of active lines depends on the game: traditional three-reel games often have one, five or nine paylines; video slots can have 9, 15, 25, or up to 1024 different paylines. Each of these paylines can award a winning combination depending on the rules of the particular game.
A slot machine’s theoretical payout percentage is set at the factory and can only be changed by swapping a tamper-proof EPROM with another one in the presence of Gaming Control Board officials. This process is time consuming and expensive, so changing the payout percentage on a slot machine often occurs only once it has been removed from service for maintenance or repairs.