All players are dealt 2 cards face down, followed by 5 cards face up. Players must make the best possible 5 card poker hand using the 5 community cards and their own face down hole cards. The best 5 card poker hand wins the hand and receives the pot.
The term comes from "flipping a coin". When playing Hold 'Em, a flip can occur, for example, when one player has a pair and another player has overcards. A flip can also be known as a "toss up" or a "horserace".