/ Dictionary / Index T twelvemonth: Meaning and Definition of Find definitions for: twelve•month Pronunciation: (twelv'munth"), [key] — n. Chiefly Brit. a year. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: twelvemonth (Thesaurus) twelvemo twelve patriarchs Related Content Daily Word Quiz: perspicacious Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language