Poker is any of a number of card games in which players wager over which hand is best according to that specific game’s rules in ways similar to these rankings.
In most modern poker games, the first round of betting begins with one or more of the players making some form of a forced bet (the blind or ante). In standard poker, each player bets according to the rank they believe their hand is worth as compared to the other players. The action then proceeds clockwise as each player in turn must either match (or “call”) the maximum previous bet, or fold, losing the amount bet so far and all further involvement in the hand. A player who matches a bet may also “raise” (increase) the bet. The betting round ends when all players have either called the last bet or folded. If all but one player folds on any round, the remaining player collects the pot without being required to reveal their hand. If more than one player remains in contention after the final betting round, a showdown takes place where the hands are revealed, and the player with the winning hand takes the pot.
Poker has many variations, all following a similar pattern of play and generally using the same hand ranking hierarchy. There are four 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 now 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 almost always played in a more complex form to allow for additional strategy.
Stud poker
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, seven-card stud, deals two extra cards to each player (three face-down, four face-up) from which they must make the best possible 5-card hand.
Draw poker
Five-card draw: A complete hand is dealt to each player, face-down. Then each player must place an ante to the pot. They can then see their cards and bet accordingly. After betting, players can discard up to three cards and take new ones from the top of the deck. Then, another round of betting takes place. Finally, each player must show his or her cards and the player with the best hand wins.
Community card poker
Also known as “flop poker”, community card poker is a variation of stud poker. Players are dealt an incomplete hand of face-down cards, and then a number of face-up community cards are dealt to the centre 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 card family.
There are several methods for defining the structure of betting during a hand of poker. The three most common structures are known as “fixed-limit”, “pot-limit”, and “no-limit”. In fixed-limit poker, betting and raising must be done by standardised amounts. For instance, if the required bet is X, an initial bettor may only bet X; if a player wishes to raise a bet, they may only raise by X. In pot-limit poker, a player may bet or raise any amount up to the size of the pot. When calculating the maximum raise allowed, all previous bets and calls, including the intending raiser’s call, are first added to the pot. The raiser may then raise the previous bet by the full amount of the pot. In no-limit poker, a player may wager their entire betting stack at any point that they are allowed to make a bet. In all games, if a player does not have enough betting chips to fully match a bet, they may go “all-in”, allowing them to show down their hand for the amount of chips they have remaining.

While typical poker games award the pot to the highest hand as per the standard ranking of poker hands, there are variations where the best hand, and thus the hand awarded the pot, is the lowest-ranked hand instead. In such games the best hand contains the lowest cards rather than the highest cards; some variations may be further complicated by whether or not hands such as flushes and straights are considered in the hand rankings. There are also games where the highest and lowest hands divide the pot between them, known as “high low split” games.

Other games that use poker hand rankings may likewise be referred to as poker. Video poker is a single-player video 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.

Strip poker is a traditional poker variation where players remove clothing when they lose bets. Since it depends only on the basic mechanic of betting in rounds, strip poker can be played with any form of poker; however, it is usually based on simple variants with few betting rounds, like five card draw.