/ Dictionary / Index I in-box: Meaning and Definition of Find definitions for: in-box Pronunciation: (in'boks"), [key] — n. a boxlike tray, basket, or the like, as on a desk, for holding incoming mail, messages, or work. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. inbounds line inbreathe Related Content Daily Word Quiz: spectral Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language