/ Dictionary / Index T trisulfide: Meaning and Definition of Find definitions for: tri•sul•fide Pronunciation: (trī-sul'fīd, -fid), [key] — n. Chem. a sulfide containing three sulfur atoms. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. trisubstituted trisyllable Related Content Daily Word Quiz: reclusive Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language