Where does “Prusa” come from?

Prusa (Latin) comes from Ancient Greek Προῦσα, from Ancient Greek Προυσίας.

Ancestry of “Prusa”, step by step

Step	Language	Word	Meaning
1	Ancient Greek	Προῦσα	—
2	Ancient Greek	Προυσίας	—

Prusa — Etymology, Origin & Word History | Etymology Explorer