Where does “нерв” come from?

нерв (Russian) comes from Latin nervus, from Proto-Indo-European (s)new-.

нерв (Russian): nerve

Definitions

Step	Language	Word	Meaning
1	Latin	nervus	A sinew, tendon, nerve, muscle; A cord, string or...
2	Proto-Indo-European	(s)new-	—

нерв — Etymology, Origin & Word History | Etymology Explorer