Where does “bocój” come from?

bocój (Polish) comes from Polish bok, from Old Polish bok, from Proto-Slavic bokъ — side.

Ancestry of “bocój”, step by step

StepLanguageWordMeaning
1Polishbokside
2Old Polishbokside, flank
3Proto-Slavicbokъside
Every word from Proto-Slavic bokъ →Every word from Old Polish bok →Every word from Polish bok →