Poker is a card game in which players place bets on who has the best hand (the group of cards you're holding) according to variable rules depending on the type of poker you're playing. The game uses a standard 52-card deck, but the number of cards you use depends on the type of game.
The card game of poker was developed in the United States at some point during the early 19th century, drawing its name and basic concept from much earlier European games. Since its early beginnings, poker has grown to become an extremely popular pastime throughout the world.