The highest possible
hand in poker. Playing Hold 'em, if you hold As, 3s and the board is Qs, 8s, Kd, 2s, 9c you are said to be holding "the nuts." The terminology is said to refer to the fact that poker is a partial information
game, meaning that when you
bet, you don't know if you're winning or losing. This being the case, you have to have "nuts" (as in testicles) to have the nerve to
bet. The only case when you can
bet in poker without "testicles" would be if you had the best possible hand and could not be beaten, hence the term "nuts"