Where does “Cernătoiu” come from?

Cernătoiu (Romanian) comes from Romanian Cernat, from Romanian cern, from Old Church Slavonic чрьнъ, from Proto-Slavic čьrnъ, from Proto-Balto-Slavic kiršnas, from Proto-Indo-European kr̥snós, from Proto-Indo-European kers- — black, dirty; run; to run.

Ancestry of “Cernătoiu”, step by step

StepLanguageWordMeaning
1RomanianCernat—
2Romaniancernfirst-person singular present indicative of...
3Old Church Slavonicчрьнъblack
4Proto-Slavicčьrnъblack
5Proto-Balto-Slavickiršnasblack
6Proto-Indo-Europeankr̥snósblack; dark, dusky
7Proto-Indo-Europeankers-black, dirty; run; to run
Every word from Proto-Indo-European kers- →Every word from Proto-Indo-European kr̥snós →Every word from Proto-Balto-Slavic kiršnas →