/ Dictionary / Index T trefoil knot: Meaning and Definition of Find definitions for: tre'foil knot" Pronunciation: [key] a knot having the form of a trefoil. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. trefoil arch trehala 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