Poker is a family of card games that are played worldwide in various forms. All games have similar rules but can differ in the number of cards, the order in which cards are dealt and how much money is involved.

Poker typically involves betting in a series of rounds, called betting intervals. At the end of each betting interval, the last player to raise calls if he meets his previous bet, or folds if he does not meet it.

The rank of a standard poker hand is determined by its odds (probability)—the higher the probability, the more likely it is to win. In games with wild cards, the highest possible hand is five of a kind, which beats any straight flush or three-card royal flush, while the lowest possible hand is seven-five-four-three in two suits.

Players often bluff by betting that they have the best hand when in fact they do not, or by playing weak hands to force other players to call a bet. A bluff is considered a strategic move if it wins the pot.

The game is based on a deck of 52 cards, sometimes with a single joker. The deal is usually done with a single pack, but in clubs and among top players, a second pack of contrasting colors may be used. The turn to deal and turn to bet always pass clockwise around the table. Before the first deal, each player posts a small and big blind.