membrane

noun

Etymology: Late Middle English, borrowed from Latin membrāna (“skin or membrane that covers parts of the body”), from membrum (“a limb or member of the body”) + -āna. Doublet of membrana.

1. A flexible enclosing or separating tissue forming a plane or film and separating two environments.
2. A flexible enclosing or separating tissue forming a plane or film and separating two environments.

   “The animal was breathing oxygen that permeated from the water through panels of membrane while carbon dioxide and other unwanted gases moved in the opposite direction—from the animal's enclosed atmosphere into the water.”

   “Then they backed the membrane with a gel matrix containing a perfluorocarbon (PFC) propellant and fluorescent "nanobullets" about a micron wide, and hit it with ultrasound.”

3. A flexible enclosing or separating tissue forming a plane or film and separating two environments.
4. A piece of parchment forming part of a roll.