membrane

American  

[mem-brayn] / ˈmɛm breɪn /

noun

• membranes
  plural

1. Anatomy. a thin, pliable sheet or layer of animal or vegetable tissue, serving to line an organ, connect parts, etc.

2. Cell Biology. the thin, limiting covering of a cell or cell part.

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membrane British  

/ ˈmɛmbreɪn /

noun

1. any thin pliable sheet of material

2. a pliable sheetlike usually fibrous tissue that covers, lines, or connects plant and animal organs or cells

3. biology a double layer of lipid, containing some proteins, that surrounds biological cells and some of their internal structures

4. physics a two-dimensional entity postulated as a fundamental constituent of matter in superstring theories of particle physics

5. a skin of parchment forming part of a roll

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membrane Scientific  

/ mĕm′brān′ /

1. A thin, flexible layer of tissue that covers, lines, separates, or connects cells or parts of an organism. Membranes are usually made of layers of phospholipids containing suspended protein molecules and are permeable to water and fat-soluble substances.

2. See cell membrane

3. Chemistry A thin sheet of natural or synthetic material that is permeable to substances in solution.

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Other Word Forms

Derived Forms

• intermembrane
  adjective
• membraneless
  adjective

Inflected Forms

Nouns

• membranes
  plural

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Etymology

Origin of membrane

1375–1425; late Middle English; Middle English membraan parchment < Latin membrāna. See member, -an

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Explanation

A membrane is a thin layer of something. For an example of a membrane, you don’t have to look far: your skin is a kind of membrane. Membranes are thin and flexible, but usually still strong enough to protect what’s inside or underneath them. Biologists often study membranes, such as those that surround your cells and organs. There are also membranes that don’t have anything to do with biology. A high-tech jacket might have a waterproof membrane to keep you dry in the rain.

Example Sentences

See Examples For:

membrane membranes

It is a very small protein embedded in cell membranes and has been associated with processes involving membrane organization and cellular transport.

From Science Daily ● Sep. 19, 2026

The MAL gene produces a small membrane protein called Mal.

From Science Daily ● Sep. 19, 2026

The researchers combined electrical stimulation with rapid freezing to capture tiny membrane changes in mouse and human brain slices.

From Science Daily ● Sep. 17, 2026

In those settings, the beading can accompany damage to the cell membrane and the internal framework that helps maintain the axon's structure.

From Science Daily ● Sep. 17, 2026

Each day, millions of meteorites fall against the outer limits of the membrane and are burned to nothing by the friction.

From "The Lives of a Cell" by Lewis Thomas

These fatty molecules make up the membranes surrounding neurons, contribute to the myelin insulation that protects nerve fibers, and play important roles in communication between brain cells.

From Science Daily ● Oct. 13, 2026

It contains an antimicrobial peptide capable of damaging bacterial membranes, creating holes that can rupture the cells.

From Science Daily ● Sep. 28, 2026

Think mushroom leather, spider-silk filaments, membranes of algae.

From The Wall Street Journal ● Sep. 19, 2026

In the 1980s, freezes ruptured oranges’ cell membranes and turned new growth black.

From The Wall Street Journal ● Sep. 19, 2026

The rainwater would seep down gently and the delicate membranes would not be crushed or broken before the emergence of tiny fingers, roots, and leaves pressing out in all directions.

From "Ceremony:" by Leslie Marmon Silko

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Related Words

• sheath
• sheet

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