Diocese
In ecclesiastical usage, the sphere of jurisdiction of a bishop. The word is of secular origin, having been employed to describe an administrative division in the Roman Empire. The pattern was adapted by the Christian Church, with province and dioceses controlled by metropolitan and bishops. In the Western Church, nevertheless, there was a certain flexibility: up to the Middle Ages it was not unknown for a metropolitan to refer to the province as his diocese, and to his own bishopric as his parish. The Eastern Orthodox Church still retains a similar practice, using “diocese” to denote the patriarch's territorial sphere, and “parish” to indicate the area for which a bishop is responsible.