Mem"brane (?), n. [F., fr. L. membrana the skin that covers the separate members of the body, fr. L. membrum. See Member.] Anat.
A thin layer or fold of tissue, usually supported by a fibrous network, serving to cover or line some part or organ, and often secreting or absorbing certain fluids.
⇒ The term is also often applied to the thin, expanded parts, of various texture, both in animals and vegetables.
Adventitious membrane, a membrane connecting parts not usually connected, or of a different texture from the ordinary connection; as, the membrane of a cicatrix. -- Jacob's membrane. See under Retina. -- Mucous membranes Anat., the membranes lining passages and cavities which communicate with the exterior, as well as ducts and receptacles of secretion, and habitually secreting mucus. -- Schneiderian membrane. Anat. See Schneiderian. -- Serous membranes Anat. , the membranes, like the peritoneum and pleura, which line, or lie in, cavities having no obvious outlet, and secrete a serous fluid.
© Webster 1913.