A deacon is a member of the diaconate, an office in Christian churches that is generally associated with service of some kind, but which varies among theological and denominational traditions.
Major Christian denominations, such as the Catholic Church, the Oriental Orthodox Churches, the Eastern Orthodox Church, Lutheranism, Presbyterianism, Methodism, and Anglicanism, view the diaconate as an order of ministry.
The priesthood is the office of the ministers of religion, who have been commissioned ("ordained") with the holy orders of the Catholic Church. Technically, bishops are a priestly order as well; however, in common English usage priest refers only to presbyters and pastors (parish priests). The church's doctrine also sometimes refers to all baptised members (inclusive of the laity) as the "common priesthood", which can be confused with the ministerial priesthood of the ordained clergy.
The church has different rules for priests in the Latin Church–the largest Catholic particular church–and in the 23 Eastern Catholic Churches. Notably, priests in the Latin Church must take a vow of celibacy, whereas most Eastern Catholic Churches permit married men to be ordained. Deacons are male and usually belong to the diocesan clergy, but, unlike almost all Latin Church (Western Catholic) priests and all bishops from Eastern or Western Catholicism, they may marry as laymen before their ordination as clergy. The priesthood is a vocation for men; a similar but distinct vocation for women is the sisterhood. The Catholic Church teaches that when a man participates in priesthood after the Sacrament of Holy Orders, he acts in persona Christi Capitis, representing the person of Christ.
In the Roman Catholic Church, the term minister is used with various meanings. Most commonly, the word refers to a person, either lay or ordained, who is commissioned to perform some act on behalf of the Catholic Church. It is not a particular office or rank of clergy, as is the case in some other Christian organisations; rather, minister may be used as a collective term for vocational or professional pastoral leaders including clergy (bishops, deacons, priests) and non-clergy (theologians and lay ecclesial ministers). It is also used in reference to the canonical and liturgical administration of sacraments, as part of some offices, and with reference to the exercise of the lay apostolate.
The Dicastery for the Clergy, formerly named Congregation for the Clergy (Latin: Congregatio pro Clericis; formerly the Sacred Congregation for the Clergy and Sacred Congregation of the Council), is the dicastery of the Roman Curia responsible for overseeing matters regarding priests and deacons not belonging to religious orders. The Congregation for the Clergy handles requests for dispensation from active priestly ministry, as well as the legislation governing presbyteral councils and other organisations of priests around the world. The Congregation does not deal with clerical sexual abuse cases, as those are handled exclusively by the Dicastery for the Doctrine of the Faith.