Unlike usage in English, "the Latin words sacerdos and sacerdotium are used to refer in general to the ministerial priesthood shared by bishops and presbyters. The words presbyter, presbyterium and presbyteratus refer to priests in the English use of the word or presbyters." According to the Annuario Pontificio 2016, as of December 31, 2014, there were 415,792 Catholic priests worldwide, including both diocesan priests and priests in the religious orders. A priest of the regular clergy is commonly addressed with the title "Father" (abbreviated Fr., in the Roman Catholic and some other Christian churches).
The state of consecrated life or monasticism is a separate, third distinct vocational state from the clergy and the laity. As an overview, there are the members of the laity—who are married or unmarried, and the clergy—the bishops, priests, and deacons. Deacons are male and usually belong to the diocesan clergy, but, unlike almost all Latin-rite (Western Catholic) priests and all bishops from Eastern or Western Catholicism, they may marry as laymen before their ordination as clergy.
Members of institutes of consecrated life, or monks, can be either clergy or non-ordained members of the religious order (male or female non-ordained religious are not to be considered laypersons in the strict sense—they take certain vows and are not free to marry once they have made solemn profession of vows; all female religious are non-ordained, they may be sisters living to some degree of activity in a communal state, or nuns living in cloister or some other type of isolation). The male members of religious orders, whether living in monastic communities or cloistered in isolation, and who are ordained priests or deacons constitute what is called the religious or regular clergy, distinct from the diocesan or secular clergy. Those ordained priests or deacons who are not members of some sort of religious order (secular priests) most often serve as clergy to a specific church or in an office of a specific diocese or in Rome.
The Old Testament describes how God made his people "a kingdom of priests and a holy nation," and within the twelve tribes of Israel, the tribe of Levi was chosen to be set apart for the liturgical service of offering sacrifice as priests. The priest was understood as a mediator between God and human beings who offers sacrifices and intercedes for the people.
The New Testament depicts Jesus as the "great high priest" of the New Covenant who, instead of offering the ritual animal sacrifices prescribed by the Jewish Law, offers himself on the cross as the true and perfect sacrifice. The Catholic priesthood is a participation in this priesthood of Christ, and therefore traces its origins to Jesus Christ himself. Thus, the New Testament says that as high priest, Jesus has made the Church "a kingdom of priests for his God and Father." All who are baptized are given a share in the priesthood of Christ; that is, they are conformed to Christ and made capable of offering true worship and praise to God as Christians. "The whole community of believers is, as such, priestly."