one-armed bandit

or onearm bandit

[ wuhn-ahrmd ]

noun

, Informal.

1. slot machine ( def 1 ).

one-armed bandit

noun

1. a fruit machine operated by pulling down a lever at one side

Word History and Origins

Origin of one-armed bandit¹

An Americanism dating back to 1935–40

Idioms and Phrases

A slot machine, as in It's amazing how many people think they can make money playing a one-armed bandit . This term refers to both appearance and function: the operating lever looks like an arm, and the machine in effect robs players, since it “wins” and keeps the player's money in an overwhelming majority of instances. [c. 1930]