Where does “Czerny” come from?

Czerny (Polish) comes from Polish Czarny, from Old Polish czarny, from Proto-Slavic *čь̀rnъ — black.

Ancestry of “Czerny”, step by step

StepLanguageWordMeaning
1PolishCzarnyblack
2Old Polishczarnyblack
3Proto-Slavic*čь̀rnъblack
Every word from Proto-Slavic *čь̀rnъ →Every word from Old Polish czarny →Every word from Polish Czarny →