One-armed Bandit Definition

wŭnärmd
noun
A slot machine for gambling operated by pulling a lever on the side.
American Heritage
Webster's New World

(gambling) A gaming machine having a long handle (the “arm" referred to in the name) at one side that one pulls down to make reels spin; the player wins money or tokens when certain combinations of symbols line up on these reels.

Wiktionary
Synonyms: