/ Dictionary / Index B back vent: Meaning and Definition of Find definitions for: back' vent" Pronunciation: [key] (in plumbing) a vent situated on the sewer side of a trap. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. backup light back walkover Related Content Daily Word Quiz: secular Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language