A slot machine known variously as a fruit machine , puggy the slots. Slot is a casino gambling machine with three or more reels which spin when a button is pushed. Slot machines are also known as one-armed bandits because they were originally operated by one lever on the side of the machine, as distinct from a button on the front panel, and because of their ability to leave the player impoverished or in debt, with bandit as a synonym for "thief". Many modern machines are still equipped with a legacy lever in addition to the button.