Poker is a card game in which players bet into a communal pot during the course of a hand, and in which the player holding the best hand at the end of the betting wins the pot. During a given betting round, each remaining player in turn may take one of four actions:

1. Check: a bet of zero that does not forfeit interest in the pot

2. Bet or Raise: a nonzero bet greater than preceding bets that all successive players must match or exceed or else forfeit all interest in the pot

3. Call: a nonzero bet equal to a preceding bet that maintains a player's interest in the pot

4. Fold: a surrender of interest in the pot in response to another player's bet, accompanied by the loss of one's cards and previous bets

Betting usually proceeds in a circle until each player has either called all bets or folded. Different poker games have various numbers of betting rounds interspersed with the receipt or replacement of cards.

Poker is usually played with a standard 4-suit 52-card deck, but a joker or other wild cards may be added. The ace normally plays high, but can sometimes play low. At the showdown, those players still remaining compare their hands - the poker player with the highest ranking poker hand wins the pot.