Where does “რუსეთი” come from?

რუსეთი (Georgian) comes from Georgian -ეთი, from Proto-Georgian-Zan *-et.

Ancestry of “რუსეთი”, step by step

StepLanguageWordMeaning
1Georgian-ეთიlocation suffix; geographical suffix
2Proto-Georgian-Zan*-et—
Every word from Proto-Georgian-Zan *-et →Every word from Georgian -ეთი →