exarch

1. (historical)In the Byzantine Empire, a governor of a distant province.

   a viceroy who governed a large province in the Roman Empire

2. In the Eastern Christian Churches, the deputy of a patriarch, or a bishop who holds authority over other bishops without being a patriarch.

   a bishop in eastern Christendom who holds a place below a patriarch but above a metropolitan

3. In these same churches, a bishop appointed over a group of the faithful not yet large enough or organized enough to constitute an eparchy or diocese.

irregular