twenty-one

(noun) the cardinal number that is the sum of twenty and one. Synonyms: 21, XXI.

(noun) a gambling game using cards; the object is to hold cards having a higher count than those dealt to the banker up to but not exceeding 21. Synonyms: blackjack, vingt-et-un.

(adj) being one more than twenty. Synonyms: 21, xxi.