/ Dictionary / Index B backwater valve: Meaning and Definition of Find definitions for: back'water valve" Pronunciation: [key] a valve for preventing flowing liquid, as sewage, from reversing its direction. Also called Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. backwater backwind Related Content Daily Word Quiz: fervor Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language