Where does “Кири́лл” come from?

Кири́лл (Russian) comes from Ancient Greek Κύριλλος, from Ancient Greek κῡ́ριος.

Ancestry of “Кири́лл”, step by step

Step	Language	Word	Meaning
1	Ancient Greek	Κύριλλος	—
2	Ancient Greek	κῡ́ριος	—

Кири́лл — Etymology, Origin & Word History | Etymology Explorer