/ Dictionary / Index O oligoclase: Meaning and Definition of Find definitions for: ol•i•go•clase Pronunciation: (ol'i-gō-klās"), [key] — n. Mineral. a kind of plagioclase feldspar occurring commonly in white crystals, sometimes shaded with gray, green, or red. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: oligoclase (Thesaurus) oligochaete oligodontia Related Content Daily Word Quiz: rustic Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language