Σεβαστος = venerable, respectable (Sebastos)
Πόλης + city (Polis)
The origins of the name are Greek. There are cities in the old Russia by that name too; that happened when the Greek missionaries left Constantinople (the mother church of Eastern Orthodoxy) to carry the word to the world, and settled in Russia as well as other places. It means: city of respect, or venerable city. The name came to our area via the Russian settlers who came down from Alaska to Ft. Ross and south of that area.This information came from a Greek, also Greek-language teacher, who was born in Greece. Look it up online if you like, so we can settle the name once and for all. Another Greek, local.