The Collaborative International Dictionary of English v.0.48:
Diocese \Di"o*cese\, n.; pl. Dioceses. [OE. diocise, OF.
diocise, F. dioc['e]se, L. dioecesis, fr. Gr. ? housekeeping,
administration, a province, a diocese, fr. ? to keep house,
manage; dia` through + ? to manage a household, ? a house.
See Economy.] (Eccl.)
The circuit or extent of a bishop's jurisdiction; the
district in which a bishop exercises his ecclesiastical
authority. [Frequently, but improperly, spelt diocess.]