D defs.my
Entry 4 senses Webster, 1913

Jackpot

/jăk'-pätˌ/ · IPA /ˈd͡ʒækpɒt/
01 n. Same as jack pot. See under jack.
  1. 1.
    Same as jack pot. See under jack. See: jack
  2. 2.
    Any larger-than-usual gambling prize formed by the accumulation of unwon bets.
  3. 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. 4.
    An unusually large success in an enterprise, either unexpected or unpredictable, esp. one providing a great financial benefit.
Phrases & compounds
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.