/ Dictionary / Index L lady's-thumb: Meaning and Definition of Find definitions for: la•dy's-thumb Pronunciation: (lā'dēz-thum"), [key] — n. a smartweed, Polygonum persicaria, of the buckwheat family, having pink or purplish flowers and lance-shaped leaves with a spot resembling a thumbprint. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. lady's-thistle lady's-tresses Related Content Daily Word Quiz: knead Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language