/ Dictionary / Index B Back Bay: Meaning and Definition of Find definitions for: Back' Bay' Pronunciation: [key] a prosperous residential and commercial area of Boston, Massachusetts. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. backbar backbeat Related Content Daily Word Quiz: frugal Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language