/ Dictionary / Index A antoninianus: Meaning and Definition of Find definitions for: an•to•nin•i•a•nus Pronunciation: (an"tu-nin"ē-ā'nus), [key] — pl. -ni a Roman coin of the 3rd century a.d., originally of silver but later debased. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. Antonia Antoninus 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