From Proto-Iranian *jnú, from *ȷ́nú, from Proto-Indo-Iranian *ȷ́ā́nu, from Proto-Indo-European *ǵónu (“knee”). Cognate with Middle Persian [script needed] (šnwk' /⁠šnōg⁠/) and Avestan 𐬲𐬥𐬎 (žnu).