Card combinations refer to the various ways in which cards can be arranged or combined. Two of the most common card combinations are MELDS and skats. MELDS are combinations of three or more cards of the same rank, such as three kings or four aces. Skats are combinations of two cards of the same rank, such as two jacks or two queens. Both MELDS and skats are used in many card games, including rummy, bridge, and poker.