membrane (n.)youdaoicibaDictYouDict[membrane 词源字典]
early 15c., "thin layer of skin or tissue," a term in anatomy, from Latin membrana "a skin, membrane; parchment (skin prepared for writing)," from membrum "limb, member of the body" (see member). The etymological sense is "that which covers the members of the body."[membrane etymology, membrane origin, 英语词源]