IPA: /ˈɛθnɑrk/
KK: /ˈɛθnɑrk/
A leader or governor of a specific group of people or a region, often in a historical or political context.
The ethnarch was responsible for maintaining order and representing the interests of his people to the empire.
Ethnarch is formed from "ethnos" (meaning nation or people) and "archon" (meaning ruler or leader). The term refers to a leader or ruler of a specific ethnic group or nation.
Think of a ruler ('archon') of a specific people or nation ('ethnos') — that's what an ethnarch is.