Where does “Ust-Luga” come from?

Ust-Luga (English) comes from Russian Усть-Луга, from Russian у́стье, from Proto-Slavic ustьje, from Proto-Slavic ustà, from Proto-Indo-European h₃éh₁os — mouth.

Ancestry of “Ust-Luga”, step by step

Step	Language	Word	Meaning
1	Russian	Усть-Луга	—
2	Russian	у́стье	—
3	Proto-Slavic	ustьje	—
4	Proto-Slavic	ustà	—
5	Proto-Indo-European	h₃éh₁os	mouth

Every word from Proto-Indo-European h₃éh₁os →

Ust-Luga — Etymology, Origin & Word History | Etymology Explorer