- Biology.
- A thin, pliable layer of tissue covering surfaces or separating or connecting regions, structures, or organs of an animal or a plant.
- Cell membrane.
- A piece of parchment.
- Chemistry. A thin sheet of natural or synthetic material that is permeable to substances in solution.
[Latin membrāna, skin, from membrum, member of the body.]
membranal mem'bra·nal (-brə-nəl) adj.




