/ Dictionary / Index M menarche: Meaning and Definition of Find definitions for: men•ar•che Pronunciation: (mu-när'kē, me-), [key] — n. Physiol. the first menstrual period; the establishment of menstruation. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: menarche (Thesaurus) Menander Menasha Related Content Daily Word Quiz: careening Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language