Jackpot: The largest amount of money given on a slot machine or video poker machine that usually requires an attendant of the casino to "hand pay" the winner.

Jacks or Better: In some poker games it’s the minimum hand needed to win. This is mainly seen in 5 card draw poker.

Joker: The only non suited card in a deck that is sometimes used as a wild card.

Juice: The profit made by the casino. Often this is called vigorous.