noun, plural: membranes
(1) (biology) A thin layer of tissue covering a surface or lining a cavity, space or organ.
(2) (biology) A cell membrane.
(3) (chemistry) A thin pliable sheet of material that is permeable to substances in solution.
A biological membrane functions by protecting the surface or bodily organ. It acts as a barrier against injurious substances. It also acts as a film or covering separating two regions. It may also connect structures or organs of an animal or a plant.
Word origin: Latin membrāna, skin, from membrum, member of the body.