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

Individuals who had experienced greater cognitive decline tended to have fewer large nerve fibers, along with an abnormal buildup of unhealthy myelin.

From Science Daily ● Oct. 17, 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

"This shows that the cells which make myelin are far more varied in their chemistry than their genes alone would suggest," says Luca Fusar Bassini.

From Science Daily ● 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

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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