Table and rules
Kicker in poker
Definition
The highest side card in your hand that is not part of the made combination; it breaks ties between equal hands.
When two players have the same pair or the same two pair, the better kicker wins. Only the cards needed to complete the five-card hand count, so the kicker may be on the board or in your hand.
A weak kicker is why a hand such as A5 loses to AK on an ace-high flop even though both have top pair.
Example
Board A♦7♣3♠, you have A♣K♠, your opponent has A♥9♠: both have a pair of aces, but your king kicker beats the nine.