Definition of "eparchy"

(historical, Ancient Rome) A district of the Roman Empire at the third echelon

(historical, Ancient Greece, Roman Empire, Byzantine Empire) A provincial government or office headed by an eparch in the Greek-speaking Eastern Roman Empire (akin to a prefecture governed by a prefect in the Latin-speaking Western Roman Empire)

(historical) An administrative sub-provincial unit in post-Ottoman independent Greece.

(Christianity) In pre-schism Christian Church, a province under the supervision of the metropolitan.  examples

(Christianity) In Eastern Christendom, a diocese of a bishop.  examples