/ Dictionary / Index B black opal: Meaning and Definition of Find definitions for: black' o'pal Pronunciation: [key] — Mineral. Mineral. a dark variety of opal having the characteristic opaline play of color. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. black olive blackout Related Content Daily Word Quiz: portent Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language