Poker is a card game in which players compete to make the best possible five-card hand using some combination of their own cards and the community cards that are dealt. In its earliest form, each player is dealt a complete hand of five cards and a round of betting ensues in which players may raise and reraise. In its later forms, like draw poker, the players are allowed to discard cards from their hand and be dealt replacements.

In the latter form, there is usually a nominal dealer button (or buck) that rotates among the players to indicate who is acting as dealer for each hand. One of the players acts as the small blind and the other as the big blind, which require forced bets from all players before the cards are dealt (if no ante is placed). Each player is given two cards face down, which are called hole cards.

The game of poker is a game of chance and skill, with luck always playing an important role in the outcome of any hand. However, those players who study the game and play sound strategy have the greatest chances of winning.

Like many card games, poker has a number of official rules that must be followed. These rules are designed to protect players from misunderstandings and ensure that the game is fair for everyone. The game also has a body that manages these rules, the Professional Tournament Directors Association (or Poker TDA). It is a group of professional card players who run large live and online poker events around the world.