English

myelin

Myelin comes from Ancient Greek μυελός ‘marrow’, from μυών ‘cluster of muscles’, and perhaps ultimately from Proto-Indo-European *múHs ‘mouse’.

attested reconstructed ? uncertain or disputed deepest recorded ancestor

¹ Wiktionary, Ancient Greek μῦς
² Wiktionary, Ancient Greek μυών
³ Wiktionary, Ancient Greek μυελός, which cites Chantraine, Beekes
⁴ Wiktionary, English myelin
Earliest quotation in Wiktionary’s entry: 1868, Edmund Montgomery, On the Formation of so-called Cells in Animal Bodies: “As the result of prolonged action of water upon…”.

Lineage

Proto-Indo-Europeanc. 4500–2500 BCE*múHs1Wiktionary, Ancient Greek μῦς‘mouse’uncertain
Proto-Hellenicc. 2200–1600 BCE*mū́s1Wiktionary, Ancient Greek μῦςuncertain
Ancient Greekc. 800–300 BCEμῦς2Wiktionary, Ancient Greek μυών‘mouse’uncertain
Ancient Greekc. 800–300 BCEμυών3Wiktionary, Ancient Greek μυελός, which cites Chantraine, Beekesmuṓn‘cluster of muscles’uncertain
Ancient Greekc. 800–300 BCEμυελός4Wiktionary, English myelinmuelós‘marrow’
Englishearliest quotation 1868myelin4Wiktionary, English myelin. Earliest quotation in Wiktionary’s entry: 1868, Edmund Montgomery, On the Formation of so-called Cells in Animal Bodies: “As the result of prolonged action of water upon…”

noun A white, fatty material, composed of lipids and lipoproteins, that surrounds the axons of nerves.

Sources: Wiktionary, “myelin”; the older steps come from the Wiktionary entries for Ancient Greek μῦς, Ancient Greek μυών, Ancient Greek μυελός. By Wiktionary contributors, CC BY-SA 4.0, via kaikki.org (dump of Oct 3 2026); text adapted and restructured. Language periods are conventional ranges, not dates for this word. License.