/ Dictionary / Index M Mithraism: Meaning and Definition of Find definitions for: Mith•ra•ism Pronunciation: (mith'ru-iz"um), [key] — n. an ancient Persian religion in which Mithras was worshiped, involving secret rituals to which only men were admitted: a major competitor of Christianity in the Roman empire during the 2nd and 3rd centuriesa.d. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: mithraism (Thesaurus) Mithraeum Mithras Related Content Daily Word Quiz: immense Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language