Kicker

The side card that breaks ties between hands of the same rank

Definition

The kicker is the card in your hand that isn't part of the main combination but breaks ties. When two players have the same pair, the kicker's rank decides the winner — a nuance that costs players who ignore it an enormous amount of money. The kicker is at the heart of the domination concept: AK dominates AQ, AJ and AT, because on an ace-high board both players hold the same pair but AK wins on the kicker. That's precisely why tight early-position ranges are built around hands with good kickers, and why "pretty" hands like A8o or KTo are standard folds UTG: when they hit their pair and face aggression, they're dominated far too often. Careful: the kicker must be part of the best 5 cards. On a Q-Q-9-9-5 board, with A2 against K3, the ace does win (two pair Q-9 with an ace kicker against a king kicker). But on an A-K-Q-J-4 board, AT and A2 split the pot: the T or 2 kicker doesn't play, since the best 5 cards are A-K-Q-J plus the highest community card.