/ Dictionary / Index M moonstone: Meaning and Definition of Find definitions for: moon•stone Pronunciation: (mn'stōn"), [key] — n. Also calleda semitransparent or translucent, opalescent, pearly-blue variety of adularia, used as a gem. any of several adularescent feldspars, as certain varieties of albite, labradorite, or oligoclase, used as gems. (not used technically) any milky or girasol stone used as a gem. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: moonstone (Thesaurus) moonshot moonstruck Related Content Daily Word Quiz: fabricate Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language