/ Dictionary / Index T trunnion: Meaning and Definition of Find definitions for: trun•nion Pronunciation: (trun'yun), [key] — n. either of the two cylindrical projections on a cannon, one on each side for supporting the cannon on its carriage. any of various similar supports for machinery. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. trunnel Truro Related Content Daily Word Quiz: frugal Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language