Where does “Cyril” come from?

Cyril (Slovak) comes from Ancient Greek Κύριλλος, from Ancient Greek κῡ́ριος.

Ancestry of “Cyril”, step by step

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

Cyril — Etymology, Origin & Word History | Etymology Explorer