Any larger-than-usual gambling prize formed by the accumulation of unwon bets.
3.
The highest gambling prize awarded in a gambling game in which smaller prizes are also awarded, especially such a prize on a slot machine.
4.
An unusually large success in an enterprise, either unexpected or unpredictable, esp. one providing a great financial benefit.
hit the jackpot to receive an unexpectedly large (or the largest possible) benefit from an enterprise; as, after prospecting for years, he finally hit the jackpot when he discovered a silver lode.
... he was going to keep the jackpot. Not by a long shot. Mallory encephalopathed Easy Money to his side and pulled himself to his feet with the help of the left stirrup and hung his helmet on the pommel. Then he picked up his spear and clambered into the saddle. "We're not beat yet, Easy ... — A Knyght Ther Was • Robert F. Young
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