Poker is a card game in which players wager money (or chips) against each other. The game has a long history and many variations. The game is played in private homes, in casinos, and over the Internet. It is sometimes considered the national card game of the United States, and its play and jargon are deeply embedded in American culture.

The basic rules of poker are the same in all variants. A player must have a hand of cards and must bet to win the pot (the sum of all bets placed during one deal). Players may choose to call a bet, raise it, or fold. When a player calls, they must match the previous bet in order to remain in the game. When a player raises, they increase the amount of money that is being put into the pot. If they do not raise, they must fold and forfeit their rights to the original pot or any side pots.

The rank of poker hands is determined by their odds of winning. The highest hand is five of a kind, which contains three cards of the same rank and two matching unmatched cards. The lowest hand is a pair, which consists of two cards of the same rank. Ties are broken by the highest unmatched cards and then by secondary pairs (in a full house, for example). In some games, the suits have no relative rank. Players may also use wild cards.