/ Dictionary / Index M mucous membrane: Meaning and Definition of Find definitions for: mu'cous mem'brane Pronunciation: [key] a lubricating membrane lining an internal surface or an organ, as the alimentary, respiratory, and genitourinary canals. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. mucous mucoviscidosis Related Content Daily Word Quiz: vertigo Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language