/ Dictionary / Index B baby boom: Meaning and Definition of Find definitions for: ba'by boom" Pronunciation: [key] a period of sharp increase in the birthrate, as that in the U.S. following World War II. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. baby book baby boomer Related Content Daily Word Quiz: rustic Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language