my·​e·​lin | \ ˈmī-ə-lən How to pronounce myelin (audio) \

Definition of myelin

: a soft white material that forms a thick layer around the axons of some neurons and is composed chiefly of lipids (such as cerebroside and cholesterol), water, and smaller amounts of protein

Other Words from myelin

myelinic \ ˌmī-​ə-​ˈli-​nik How to pronounce myelin (audio) \ adjective

Examples of myelin in a Sentence

Recent Examples on the Web Blocking seizures with the anti-epilepsy drug ethosuximide (sold under the name Zarontin by Pfizer) reduced the thickening of the myelin. Jonathan Wosen, STAT, 4 May 2022 In this case, your immune system mistakenly attacks your myelin and damages the myelin sheath. Sara Gaynes Levy, SELF, 7 Mar. 2022 When the myelin is damaged, your nerve signals can’t function properly, according to the U.S. National Library of Medicine. Korin Miller, SELF, 12 Nov. 2021 Glatiramer acetate is injected under your skin to help prevent your immune system from attacking your myelin. Korin Miller, SELF, 12 Nov. 2021 But scientists don’t know if extra myelin is a cause or an effect of misophonia. Alison Escalante, Forbes, 14 Sep. 2021 The diagnosis is confirmed if a patient has damaged myelin in at least two areas of the central nervous system and has had at least two relapses, according to the American Academy of Family Physicians. Jack Guy, CNN, 11 Aug. 2021 The inflammation then damages the myelin that covers and protects the nerve fibers, the Mayo Clinic explains, which can cause sharp pain in the lower back, weakness in the limbs, odd sensations of numbness or tingling, and bowel or bladder issues. Sarah Jacoby, SELF, 10 Sep. 2020 One of the most surprising of these new findings involves myelin. R. Douglas Fields, Scientific American, 12 Mar. 2020 See More

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'myelin.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

First Known Use of myelin

1866, in the meaning defined above

History and Etymology for myelin

borrowed from German Myelin, from Greek myelós "bone marrow" + German -in -in entry 1 — more at myelo-

Note: The term was introduced by Rudolf virchow in "Ueber das ausgebreitete Vorkommen einer dem Nervenmark analogen Substanz in den thierischen Geweben," Archiv für pathologische Anatomie und Physiologie und für klinische Medicin, 6. Band (1854), p. 571

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Last Updated

12 May 2022

Cite this Entry

“Myelin.” Dictionary, Merriam-Webster, Accessed 27 May. 2022.

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More Definitions for myelin


my·​e·​lin | \ ˈmī-ə-lən How to pronounce myelin (audio) \

Medical Definition of myelin

: a soft white material of lipid and protein that is secreted by oligodendrocytes and Schwann cells and forms a thick sheath about axons — see myelin sheath

Other Words from myelin

myelinic \ ˌmī-​ə-​ˈlin-​ik How to pronounce myelin (audio) \ adjective

More from Merriam-Webster on myelin Encyclopedia article about myelin


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