One-Armed Bandits

Old term for slot machines.

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Called one-armed bandits because of the spin lever which players originally needed to pull to initiate the spinning of the slots reels.

The original mechanical slot machines required that a lever be pulled to set the slot machine reels spinning. This level jutted out from the side of a slot machine, and therefore looked somewhat like a the slot machine had an arm. Since there obviously was only one "arm" on the slot machine, it appeared they were "one-armed".

The bandit part of the nickname is obvious. Casinos don't exist very long if they don't maintain a house edge, so casinos have the edge on just about any bet a gambler makes on a slot machine. That means (on average) slot machines take more players' money than players take money from the slot machines. If you see that a slot machine has a payback percentage less than 100% (and the vast majority will be less than 100%), you know you are playing at a disadvantage -- no matter how slight.

So slot machines are one-armed bandits. The term is used far and wide, and slots are called one-armed bandits throughout North America and the United Kingdom.

Today, electronic slot machines have no need for a spin lever. You won't find many machines with a lever on them anymore, unless it's a vintage model or some kind of throwback. Regardless, players are likely to go on referring to slot machines as one-armed bandits for a long time yet.