Jack-O'-Lantern

Part of speech: noun (n.)

1. See Jack-with-a-lantern, under 2d Jack. JACKPOT Jackpot

2. 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.

3. 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.