myelin

American  

[mahy-uh-lin] / ˈmaɪ ə lɪn /

Also myeline

noun

Biology.

1. a soft, white, fatty material in the membrane of Schwann cells and certain neuroglial cells: the substance of the myelin sheath.

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myelin British  

/ ˈmaɪɪˌliːn, ˈmaɪɪlɪn /

noun

1. a white tissue forming an insulating sheath ( myelin sheath ) around certain nerve fibres. Damage to the myelin sheath causes neurological disease, as in multiple sclerosis

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myelin Scientific  

/ mī′ə-lĭn /

1. A whitish, fatty substance that forms a sheath around many vertebrate nerve fibers. Myelin insulates the nerves and permits the rapid transmission of nerve impulses. The white matter of the brain is composed of nerve fibers covered in myelin.

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Other Word Forms

• myelinic
  adjective

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Etymology

Origin of myelin

First recorded in 1865–70; myel- + -in ²

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Example Sentences

See Examples For:

myelin

These experiments provided evidence that declining NRF2 activity can directly disrupt oligodendrocyte function, potentially triggering changes in myelin and nerve fibers that contribute to cognitive decline.

From Science Daily ● Oct. 17, 2026

Meanwhile, levels of galactosyl ceramide, an important component of myelin, increased sharply throughout much of the brain's white matter.

From Science Daily ● Oct. 13, 2026

The emergence of myelin is given particular emphasis, being compared by cell biologist Robin Franklin to the “invention of microprocessors in computing.”

From The Wall Street Journal ● Oct. 13, 2026

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

Throughout adolescence, the brain is busily lining important neural pathways with a fatty sheath called myelin.

From "The 57 Bus" by Dashka Slater

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