Where does “Зи́на” come from?

Зи́на (Russian) comes from Russian Зинаи́да, from Ancient Greek Ζηναΐς.

Ancestry of “Зи́на”, step by step

Step	Language	Word	Meaning
1	Russian	Зинаи́да	—
2	Ancient Greek	Ζηναΐς	—

Зи́на — Etymology, Origin & Word History | Etymology Explorer