/ Dictionary / Index B bye-bye: Meaning and Definition of Find definitions for: bye-bye Pronunciation: (interj.bī'bī'n., adv.bī'bī&sec), [key] — interj. good-bye. —n. sleep. —adv. to leave; depart; go out. to go to sleep; go to bed. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: bye-bye (Thesaurus) bye-blow byelaw 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