/ Dictionary / Index B black chaff: Meaning and Definition of Find definitions for: black' chaff' Pronunciation: [key] — Plant Pathol. Plant Pathol. a disease of wheat, characterized by dark, elongated stripes on the chaff, caused by a bacterium, Xanthomonas translucens undulosum. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. black carpet beetle black cherry Related Content Daily Word Quiz: neologism Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language