membrane

American  

[mem-breyn] / 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

Etymology

Origin of membrane

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

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

PEM refers to proton exchange membrane electrolysis, a technology that uses an electrically powered membrane system to separate water into hydrogen and oxygen.

From Science Daily ● Aug. 11, 2026

She shared that her cancer had spread to her peritoneum, a membrane that lines the abdominal and pelvic cavities and protects internal organs.

From BBC ● Aug. 6, 2026

"We discovered that this membrane skeleton is actively regulating the nutrient uptake process of neurons," Zhou said.

From Science Daily ● Jul. 15, 2026

The fire was spreading in the membrane hidden beneath the metal roof.

From The Wall Street Journal ● Jun. 22, 2026

The superior said that the opening in the membrane should be enlarged, and that a ladder should be put in the hole, so that the bodies could be carried out.

From "Slaughterhouse-Five" by Kurt Vonnegut

They implanted the keratin membranes into rats with skull defects that were large enough that they would not normally heal on their own.

From Science Daily ● Aug. 12, 2026

The measurements revealed that the strong bonding between the membranes does more than simply hold them together.

From Science Daily ● Aug. 3, 2026

This treatment formed strong chemical bonds between the stacked membranes.

From Science Daily ● Aug. 3, 2026

During ferroptosis, oxidation damages critical molecules, particularly the fatty molecules that make up cell membranes, eventually causing the cells to break down.

From Science Daily ● Jul. 9, 2026

The roar becomes loud enough to separate membranes in the middle ear.

From "All the Light We Cannot See" by Anthony Doerr

Related Words

• sheath
• sheet