/ Dictionary / Index M mail drop: Meaning and Definition of Find definitions for: mail' drop" Pronunciation: [key] a receptacle or one of a series of pigeonholelike slots, as in an office, into which incoming mail is placed for pickup. drop (def. 12). Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: maildrop (Thesaurus) mail-cheeked maile Related Content Daily Word Quiz: perspicacious Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language