Where does “Grigory” come from?

Grigory (English) comes from Russian Григо́рий, from Ancient Greek Γρηγόριος, from Ancient Greek -ῐος, from Proto-Indo-European -yós — Creates adjectives from noun or verb stems.

Ancestry of “Grigory”, step by step

StepLanguageWordMeaning
1RussianГриго́рийGregory
2Ancient GreekΓρηγόριοςwatchful, vigilant
3Ancient Greek-ῐοςbelonging to; of”, “belonging to”, “pertaining to
4Proto-Indo-European-yósCreates adjectives from noun or verb stems
Every word from Proto-Indo-European -yós →Every word from Ancient Greek -ῐος →Every word from Ancient Greek Γρηγόριος →