A dean, in a church context, is a cleric holding certain positions of authority within a religious hierarchy. The title is used mainly in the Anglican Communion, the Roman Catholic Church, and many Lutheran denominations. A dean's assistant is called a subdean.
In the church, the Dean of the College of Cardinals and the Cardinal Vice-Dean are the president and vice-president of the college. Both are elected. Except for presiding and delegating administrative tasks, they have no authority over the cardinals, acting as primus inter pares (first among equals).
In the academic community, the Dean is the academic leader of the Faculty who presides over the Faculty Board and administration. He is deputized by a Vice-Dean and equally assisted by a Sub-Dean who can be delegated some of the academic task of the Dean, though he or she cannot preside in the absence of the Dean. The most senior Professor or a Vice-Dean is the only person who can act for a Dean in his or her absence from office.
In the Church of England and elsewhere in the Anglican Communion, the dean is the chief resident cleric of a cathedral or other collegiate church and the head of the chapter of canons. If the cathedral or collegiate church has its own parish, the dean is usually also rector of the parish. However, in the Church of Ireland the roles are often separated, and most cathedrals in the Church of England do not have associated parishes. In the Church in Wales, however, most cathedrals are parish churches, and their deans are now also vicars of their parishes.