Where does “кото́рый” come from?

кото́рый (Russian) comes from Old East Slavic которъ, from Proto-Slavic kotorъ, from Proto-Indo-European kʷóteros, from Proto-Indo-European kʷos, from Proto-Indo-European kʷ- — The primary interrogative root.

кото́рый (Russian): what, which (among a specific series)

Definitions

  1. what, which (among a specific series)

Ancestry of “кото́рый”, step by step

кото́рый traces back through two separate lines of ancestry.

via Old East Slavic которъ

StepLanguageWordMeaning
1Old East Slavicкоторъwhich, that, who, whom
2Proto-Slavickotorъwhich
3Proto-Indo-Europeankʷóteroswhich of two
4Proto-Indo-EuropeankʷosSee *kʷis
5Proto-Indo-Europeankʷ-The primary interrogative root

via Proto-Slavic *kotorъjь

StepLanguageWordMeaning
1Proto-Slavic*kotorъjь

Words derived from “кото́рый

Every word from Proto-Indo-European kʷ-Every word from Proto-Indo-European kʷosEvery word from Proto-Indo-European kʷóteros