mucous membrane n.
A membrane lining all body passages that communicate with the exterior, such as the respiratory, genitourinary, and alimentary tracts, and having cells and associated glands that secrete mucus. Also called mucosa.
The membrane that lines passageways and cavities in the body that lead to the outside, such as the mouth, gastrointestinal tract, nose, vagina, and urethra. These membranes are equipped with glands that secrete mucus.