diocese

A diocese is a territorial unit of church administration in certain Christian denominations, overseen by a bishop. The term comes from Late Latin dioecesis, from Greek dioikēsis, meaning administration or household management. In many churches the diocese defines a geographic region in which the bishop provides pastoral leadership, teaches doctrine, and governs the local church's ordained ministries and parishes.

In the Catholic Church, a diocese comprises parishes served by priests and deacons, under the authority of a bishop. Larger regions may include an archdiocese led by an archbishop, forming a metropolitan province with several suffragan dioceses. The bishop's principal church is the cathedral, which contains the bishop's ceremonial chair, or cathedra. Dioceses are governed by a curia and may include a vicar-general, chancellors, and various offices to oversee education, finances, and pastoral activities. Boundaries and creation of dioceses are typically established by papal authority and canon law.

In the Orthodox and some Oriental churches, a comparable territorial unit is often called an eparchy, also led by a bishop or archbishop. The structure usually mirrors the Catholic pattern, with metropolitans or patriarchs providing higher-level oversight over multiple sees and a synod or council for broader governance.

Anglican and many Protestant churches also use the diocese concept, with governance by a bishop and an executive body such as a diocesan synod. In these traditions the term may accompany variations in governance—ranging from episcopal to more representative or congregational models—depending on historical and regional practices.

Overall, the diocese functions as the fundamental geographic and administrative framework within which a church organizes worship, sacraments, education, and pastoral care.