Where does “Denis” come from?

Denis (Serbo-Croatian) comes from French Denis, from Latin Dionȳsius, from Ancient Greek Διονύσιος, from Ancient Greek -ῐος, from Proto-Indo-European -yós — Creates adjectives from noun or verb stems.

Ancestry of “Denis”, step by step

Step	Language	Word	Meaning
1	French	Denis	originally given in honor of a third century bishop of Paris, the patron saint of France
2	Latin	Dionȳsius	tyrant of Syracuse
3	Ancient Greek	Διονύσιος	—
4	Ancient Greek	-ῐος	belonging to; of”, “belonging to”, “pertaining to
5	Proto-Indo-European	-yós	Creates adjectives from noun or verb stems

Every word from Proto-Indo-European -yós →Every word from Ancient Greek -ῐος →Every word from Ancient Greek Διονύσιος →