/ Dictionary / Index M mortise lock: Meaning and Definition of Find definitions for: mor'tise lock" Pronunciation: [key] a lock housed within a mortise in a door or the like, so that the lock mechanism is covered on both sides. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. mortise joint mortling Related Content Daily Word Quiz: belligerent Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language