Poker is a card game in which players wager money. While the result of any particular hand depends to a significant degree on chance, it also involves skill and psychology. Players may bluff in an attempt to make opponents believe that they have the best hand, or they may raise bets when they have a good opportunity to win. The game is often played in tournaments, which are competitions involving many matches that determine the overall winner. Tournaments are common in team sports, racket sports, combat sports and board games, but they can also be found in other types of competition, such as academic or literary contests.

The game is played from a standard deck of 52 cards, although some variant games use multiple packs or add extra cards known as jokers. Cards are ranked from highest (Ace) to lowest (Jack), and the suits are spades, hearts, diamonds and clubs. Some games allow wild cards to take on any rank or suit. The highest five-card hand wins the pot. If no one has a high hand, a showdown takes place where the players reveal their cards and the player with the best hand wins the round.

Players must put some amount of money into the pot before they are dealt cards, which is known as putting in or buying in. They can then choose to call, raise or fold their cards.