/ Dictionary / Index T trisyllable: Meaning and Definition of Find definitions for: tri•syl•la•ble Pronunciation: (trī'sil"u-bul, trī-sil'-, tri-), [key] — n. a word of three syllables, as pendulum. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: trisyllable (Thesaurus) trisulfide trit. Related Content Daily Word Quiz: cygnet Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language