1) Byzantine military office 2) Form of government 3) Governor of a province 4) Herod the Great 5) Provincial ruler 
==Antiquity== The title first appears in the Hellenistic Middle East, possibly in Judea. In the First book of Maccabees the word is used three times (1 Maccabees 14:47 and 15:1-2), where Simon is referred to as the high priest and ethnarch of the Judeans.{#tag:ref|`And Simon accepted and was pleased to be high priest and to be commander and ethna....
• (n.) The governor of a province or people.
(from the article `Makarios III`) ...identified with the movement for enosis, the archbishop of Cyprus having traditionally played an important political role during the Turkish ... [4 related articles]
Eth'narch noun [ Greek ...; ... nation + ... leader, commander. See -arch .] (Gr. Antiq.) The governor of a province or people. Lew Wallace. 
ethnarch A governor of a nation or people; a ruler over a province.
noun the ruler of a province (as in the Roman Empire and Byzantine Empire) or certain religious rulers with secular authority; `the election of Makarios III to archbishop gave him the status of the ethnarch of Cyprus`
the ruler of a people, tribe, or nation.