membrane

plural membranes

1. A flexible enclosing or separating tissue forming a plane or film and separating two environments.
   1. countableuncountableanatomyA mechanical, thin, flat flexible part that can deform or vibrate when excited by an external force.
   2. countableuncountableanatomyA flexible or semiflexible covering or waterproofing whose primary function is to exclude 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.

      2016 January 14, Jessica Hall, “Nanoengineers build 'microcannons' that fire light-up bullets filled with drugs”, in ExtremeTech

      1 more example

      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.

      1964 October 2, “SYNTHETIC FILM CAN ACT AS GILL; Silicone Rubber Membrane Is Announced by G. E.”, in The New York Times, New York, N.Y.: The New York Times Company, →ISSN, →OCLC, archived from the original on 23 Nov 2025

   3. countableuncountableanatomyA microscopic double layer of lipids and proteins forming the boundary of cells or organelles.
2. countableuncountableA piece of parchment forming part of a roll.