Where does “Nyyssönen” come from?

Nyyssönen (Finnish) comes 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 “Nyyssönen”, step by step

Step	Language	Word	Meaning
1	Latin	Dionȳsius	tyrant of Syracuse
2	Ancient Greek	Διονύσιος	—
3	Ancient Greek	-ῐος	belonging to; of”, “belonging to”, “pertaining to
4	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 →