twenty-one (redirected from 21 (number))

twenty-one: see blackjack.

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blackjack

 or twenty-one

Card game whose object is to be dealt cards having a higher count than those of the dealer, up to but not exceeding 21. The dealer may use a single deck of 52 cards or two or more decks from a holder called a shoe. Aces count as 1 or 11, and face cards as 10. Depending on the rules used, bets may be placed before the deal, after each player has been dealt one card facedown, or after each player has received two cards facedown and the dealer has exposed one of his cards.