/ Dictionary / Index T thistledown: Meaning and Definition of Find definitions for: this•tle•down Pronunciation: (this'ul-doun"), [key] — n. the mature, silky pappus of a thistle. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: thistledown (Thesaurus) thistle butterfly thistle tube 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