/ Dictionary / Index A arnatto: Meaning and Definition of Find definitions for: ar•nat•to Pronunciation: (är-nat'ō, -nä'tō), [key] — pl. -tos. annatto (def. 2). Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. armyworm Arndt Related Content Daily Word Quiz: leonine Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language