one-armed bandit

US: (wun′ärmd′)

WordReference Random House Unabridged Dictionary of American English © 2025

one′-armed ban′dit  (wun′ärmd′), [Informal.]

1. Games See slot machine (def. 1).

Also, one′arm ban′dit. 

• 1935–40, American.

Collins Concise English Dictionary © HarperCollins Publishers::

one-armed bandit, one-arm bandit noun

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