/ Dictionary / Index B black flux: Meaning and Definition of Find definitions for: black' flux" Pronunciation: [key] — Metall. Metall. a reducing flux consisting of finely divided carbon and potassium carbonate. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. black flag black fly Related Content Daily Word Quiz: perspicacious Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language