Mĕm'brāne, n.

n. [Fr. membrane, It., Sp., & Lat. membrana, the skin that covers the separate members of the body, from Lat. membrum. See supra.] (Anat.) A thin, extended, soft, transparent tissue, formed by fibers interwoven like net-work, and serving to cover some part of the body, or to absorb or secrete 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, the membrane lining the retina of the eye.—Mucous membrane, the membrane lining the naturally open cavities of the body, and secreting mucus.—Schneiderian membrane, the lining membrane of the upper part of the nose, in which the nerves of the sense of smell are supposed to terminate.—Serous membrane, the membrane lining the closed cavities of the body, and secreting a lubricating fluid.