Where does “Dennis” come from?

Dennis (Cebuano) comes from English Dennis, from Middle English Denis, from Old 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 “Dennis”, step by step

Step	Language	Word	Meaning
1	English	Dennis	—
2	Middle English	Denis	—
3	Old French	Denis	—
4	Latin	Dionȳsius	tyrant of Syracuse
5	Ancient Greek	Διονύσιος	—
6	Ancient Greek	-ῐος	belonging to; of”, “belonging to”, “pertaining to
7	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 →