From Latin 'membrana' (skin), from 'membrum' (limb), from PIE *mems-ro- (flesh) — skin covering a limb.
A thin, flexible sheet of tissue that covers, lines, or connects structures in the body; also, any similar thin, pliable barrier or layer.
From Latin membrāna (skin covering a limb, thin layer of skin, parchment made from skin), from membrum (limb, body-part, organ), from PIE *mems-ro- (flesh, body part), related to *mems- (flesh, meat). The PIE root *mems- is reflected in Sanskrit māṃsa (flesh, meat), Old English mǣre (boundary, via the sense of flesh as the body's edge), Gothic mimz (flesh), and Greek mēros (thigh). Latin membrum originally meant a fleshy limb; membrāna was the skin that wrapped and
Latin 'membrāna' also meant 'parchment' — the treated animal skin used for writing. The connection is literal: parchment is a membrane, a thin layer of skin. The finest parchment, called 'vellum' (from French 'vélin,' from 'veau,' calf), was made from calf skin. So a 'membrane' in biology and