Where does “окун-” come from?

окун- (Russian) comes from Bulgarian око, from Old Church Slavonic око, from Proto-Slavic ȍko, from Proto-Balto-Slavic ak-, from Proto-Indo-European h₃ókʷs, from Proto-Indo-European h₃ekʷ- — to see; eye.

Ancestry of “окун-”, step by step

StepLanguageWordMeaning
1Bulgarianокоeye
2Old Church Slavonicокоeye; vision, sight
3Proto-Slavicȍkoeye
4Proto-Balto-Slavicak-eye
5Proto-Indo-Europeanh₃ókʷseye
6Proto-Indo-Europeanh₃ekʷ-to see; eye
Every word from Proto-Indo-European h₃ekʷ- →Every word from Proto-Indo-European h₃ókʷs →Every word from Proto-Balto-Slavic ak- →