myelin

noun

my·​e·​lin ˈmī-ə-lən 

: 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

myelinic

ˌmī-ə-ˈli-nik 

adjective

Examples of myelin in a Sentence

Recent Examples on the Web

However, their myelin levels returned to normal within two months of the race. —Monica Cull, Discover Magazine, 3 July 2025

When depleted of other energy sources, the brains of marathon runners consume their own myelin. —Rafil Kroll-Zaidi, Harpers Magazine, 18 June 2025

In his book The Talent Code, Daniel Coyle provides examples of how coaching can support creating additional myelin in your team member’s neurological network. —Bryan Powell, Forbes.com, 28 May 2025

However, their myelin levels were back to normal after two months. —Monica Cull, Discover Magazine, 3 Apr. 2025

Word History

Etymology

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

First Known Use

1866, in the meaning defined above

Phrases Containing myelin

• myelin sheath

Rhymes for myelin

• sphingomyelin

Kids Definition

myelin

noun

my·​elin

ˈmī-ə-lən

: a soft white somewhat fatty material that forms a thick layer around the axons of some neurons

Medical Definition

myelin

noun

my·​e·​lin ˈmī-ə-lən 

: 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

myelinic

ˌmī-ə-ˈlin-ik 

adjective