Diocese/ˈdaɪəsɪs/ Definition 1 of 1Pro Tip 1/3Church Organization A diocese is a key administrative unit in many Christian churches, like a district. She worked in the diocese's main office. Pro Tip 2/3Bishop's Authority A diocese is under the jurisdiction of a bishop, who leads it. The bishop discussed changes affecting the entire diocese. Pro Tip 3/3Geographic Entity A diocese has specific geographic boundaries, much like a state or province. The diocese covers all the churches in this region.