Jackpot 1. (a) See "jack pot" under jack; (b) any larger-than-usual gambling prize formed by the accumulation of unwon bets[=MW10 1(a)(2) and 1(c)]; (c) the highest gambling prize awarded in a gambling game in which smaller prizes are also awarded, especially such a prize on a slot machine. 2. (a) An unusually large success in an enterprise, either unexpected or unpredictable, esp. one providing a great financial benefit.
hit the jackpotto receive an unexpectedly large (or the largest possible) benefit from an enterprise.
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© Webster 1913.