/ Dictionary / Index M mail-out: Meaning and Definition of Find definitions for: mail-out Pronunciation: (māl'out"), [key] — n. an act or instance of mailing out a quantity of letters, circulars, or the like; mailing. a form letter, brochure, etc., mailed out. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: mail-out (Thesaurus) mail-order house mailroom Related Content Daily Word Quiz: soporific Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language