/ Dictionary / Index T touchstone: Meaning and Definition of Find definitions for: touch•stone Pronunciation: (tuch'stōn"), [key] — n. a test or criterion for the qualities of a thing. a black siliceous stone formerly used to test the purity of gold and silver by the color of the streak produced on it by rubbing it with either metal. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: touchstone (Thesaurus) touchscreen touch system 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