/ Dictionary / Index S Sunday baby: Meaning and Definition of Find definitions for: Sun'day ba"by Pronunciation: [key] — South Atlantic States (chiefly North Carolina) South Atlantic States (chiefly North Carolina). an illegitimate child. Also called Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. Sunday Sunday clothes Related Content Daily Word Quiz: paradox Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language