名詞 twenty-one:

1. the cardinal number that is the sum of twenty and one
   同義詞：21, XXI
2. a gambling game using cards; the object is to hold cards having a higher count than those dealt to the bank up to but not exceeding 21
   同義詞：blackjack, vingt-et-un

形容詞 twenty-one:

1. being one more than twenty
   同義詞：21, xxi