In the Catholic Church, Can.374 §2 of the Code of Canon Law grants to bishops the possibility to join together several neighbouring parishes into special groups, such as vicariates forane, or deaneries.
Each deanery is headed by a vicar forane, also called a dean or archpriest, who is--according to the definition provided in canon 553--a priest appointed by the bishop after consultation with the priests exercising ministry in the deanery. Canon 555 defines the duties of a dean as:
Additionally, the dean must follow the particular norms of the diocese. Canon 555 also particularly mentions that a dean must visit the parishes of the district in accord with the regulations made by the diocesan bishop.
In the Church of England and many other Anglican churches a deanery is a group of parishes forming a district within an archdeaconry. The more formal term, rural deanery, is less often used, though the superintendent of a deanery is the Rural Dean. Rural deaneries are very ancient and originally corresponded with the hundreds. The title "dean" (Latin decanus) may derive from the custom of dividing a hundred into ten tithings. In medieval times rural deans acted as officers of the diocesan bishop, but archdeacons gradually took over most of their duties. However, the office was revived during the 19th century. Modifications to deanery boundaries may be made according to the provisions of the Archdeaconries and Rural Deaneries Act of 1874 (37 & 38 Vict., cap. 63).
The deanery synod has a membership of all clergy who are licensed to a parish within the deanery, plus elected lay members from every parish. They were established in the 1970s.
The term is also often used to refer to the house, or official residence, of the dean of a cathedral. The term is also used to apply to the ecclesiastical districts of Jersey and Guernsey, which are Royal Peculiars and whose deans hold a status more nearly equivalent to an Archdeacon than a rural dean.
In the Episcopal Church, deaneries are synonymous with convocations and are headed by deans.