say it: TWEN-tee-wawn
twenty-one is a noun and adjective meaning "the cardinal number that is the sum of twenty and one". It carries 3 recorded senses.
the cardinal number that is the sum of twenty and one
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
Definitions, synonyms and semantic relations for twenty-one come from Princeton University’s WordNet. The pronunciation comes from the CMU Pronouncing Dictionary. Commonness is measured against a corpus of everyday English. Full sources and licences.