[jack.pot] n (1881) 1 a (1): a hand or game of draw poker in which a pair of jacks or better is required to open (2): a large pot (as in poker) formed by the accumulation of stakes from previous play b (1): a combination on a slot machine that wins a top prize or all the coins available for paying out (2): the sum so won c: a large fund of money or other reward formed by the accumulation of unwon prizes
2: an impressive often unexpected success or reward 3 chiefly West: a tight spot: jam