Poker

Poker is a type of card game in which players bet on the value of the card combination ("hand") in their possession, by placing a bet into a central pot. The winner is the one who holds the hand with the highest value according to an established hand rankingshierarchy, or otherwise the player who remains in the hand after all others have folded (the player who makes an un-called bet), and wins this pot.

Variations
Poker has many variations, all following a similar pattern of play and using the same hand ranking hierarchy. There are three main families of variants, largely grouped by the protocol of card-dealing and betting:
"Straight" - A complete hand is dealt to each player, and players bet in one round, with raising and re-raising allowed. This is the oldest poker family; the root of the game as currently played was a game known as Primero, which evolved into the game Three-card brag, a very popular gentleman's game around the time of the American Revolutionary War and still enjoyed in the U.K. today. "Straight" hands of five cards are sometimes used as a final showdown, but poker is currently virtually always played in a more complex form to allow for additional strategy.
Stud - Cards are dealt in a prearranged combination of face-down and face-up rounds or "streets", with a round of betting following each. This is the next-oldest family; as poker progressed from three to five-card hands, they were often dealt one card at a time, either face-down or face-up, with a betting round between each. The most popular stud variant today, 7 card stud, deals two extra cards to each player (three facedown, four faceup) from which they must make the best possible 5-card hand.
Draw - A complete hand is dealt to each player, face-down, and after betting, players are allowed to attempt to change their hand by discarding unwanted cards and being dealt new ones. 5 card draw is the most famous variation in this family.
Community - A variation of Stud, players are dealt an incomplete hand of face-down cards, and then a number of face-up "community" cards are dealt to the center of the table, each of which can be used by one or more of the players to make a 5-card hand. Texas hold-em and Omaha are two well-known variants of the Community family.
Other games that use poker hand rankings may likewise be referred to as "poker". Video poker is a single-player computer game that functions much like a slot machine; most video poker machines play draw poker, where the player bets, a hand is dealt, and the player can discard and replace cards. Payout is dependent on the hand resulting after the draw and the player's initial bet.
Another game with the "Poker" name, but with a vastly different mode of play, is called "Acey-Deucey" or "Red Dog" Poker. This game is more similar to Blackjack in its layout and betting; each player bets against the house, and then is dealt two cards. For the player to win, the third card dealt (after an opportunity to raise the bet) must have a value in between the first two. Payout is based on the odds that this is possible, based on the difference in values of the first two cards.

Game play
In casual play, the right to deal a hand typically rotates among the players and is marked by a token called a'dealer' button (or "buck"). In a casino, a house dealer handles the cards for each hand, but the button (typically a white plastic disk) is rotated clockwise among the players to indicate a nominal dealer to determine the order of betting.
One or more players are usually required to makeforced bets, usually either an ante or a blind bet (sometimes both). The dealer shuffles the cards, the player one chair to his right cuts, and the dealer deals the appropriate number of cards to the players one at a time. Cards may be dealt either face-up or face-down, depending on the variant of poker being played. After the initial deal, the first of what may be severalbetting rounds begins. Between rounds, the players' hands develop in some way, often by being dealt additional cards or replacing cards previously dealt. At the end of each round, all bets are gathered into the central pot.
At any time during a betting round, if one player bets and no opponents choose to "call" (match) the bet and instead "fold", the hand ends immediately, the bettor is awarded the pot, no cards are required to be shown, and the next hand begins. This is what makes bluffingpossible. Bluffing is a primary feature of poker, one that distinguishes it from other vying games and from other games that make use of poker hand rankings.
At the end of the last betting round, if more than one player remains, there is a showdown, in which the players reveal their previously hidden cards and evaluate their hands. The player with the best hand according to the poker variant being played wins the pot. A poker hand consists of five cards, but in some variants a player has more than five to choose from.