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

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

Working with other researchers, they examined myelin formation in additional mouse models using several different methods.

From Science Daily ● Aug. 14, 2026

They also have a major role in building myelin as the brain matures.

From Science Daily ● Aug. 14, 2026

Physical injuries can also harm myelin, and in severe cases, the resulting damage can lead to the death of entire neurons.

From Science Daily ● Aug. 14, 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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