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

Etymology

Origin of myelin

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

Example Sentences

Their findings show that the immune system begins attacking the brain's protective myelin sheath -- the fatty covering that insulates nerve fibers -- much earlier than scientists once believed.

From Science Daily • Oct. 21, 2025

Although existing treatments can help reduce inflammation, there are still no approved therapies that protect neurons or rebuild the damaged myelin sheath.

From Science Daily • Oct. 11, 2025

A compound like K102 that can restore myelin could help improve nerve signal transmission and potentially limit long-term disability.

From Science Daily • Oct. 11, 2025

This new work builds on earlier studies involving a compound called indazole chloride, which had shown promise in promoting myelin repair and regulating immune responses in mouse models of MS.

From Science Daily • Oct. 11, 2025

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

From "The 57 Bus" by Dashka Slater