In many religions, being a priest is a full time assignment, ruling out any other career. In many other religions it is a position inherited in familial line.
In the Christian context, some confusion is caused for English speakers by two different Greek words traditionally translated as priest. Both occur in the New Testament, which draws a distinction not always observed in English. The first, presbyteros (πρεσβυτερος), Latin presbyter, is traditionally translated priest; literally, it means elder. The second, hiereus ('ιερευς), Latin sacerdos, refers to priests who offer sacrifices, such as the priesthood of the Jewish Temple, or the priests of pagan gods. The Epistle to the Hebrews draws a distinction between the two types of priesthood; it teaches that atonement by Jesus Christ has made the hiereus or sacerdotal priesthood redundant, in terms of the sacrifices the Jews previously offered. Catholics and Orthodox believe that there is a new priesthood, which offers the sacrifice of Jesus in the form of the Eucharist.
In Eastern Orthodoxy, a priest is sometimes also called a "presbyter" or elder. Priests are considered clergy; a priest can only be ordained by a bishop and with the "axios" or affirmation of the laity of his parish. Only men may become priests; traditionally the minimum age has been 35 in many jurisdictions, although exceptions are made from time to time at the bishop's discretion.
In Roman Catholicism only men may become priests. Priests also cannot marry in the Latin rites of the Roman Catholic church. In most branches of the Anglican church both men and women can become priests and there are no restrictions on marriage. See clerical celibacy for more details of marriage rules in Catholic and Orthodox churches. Among the most significant liturgical acts reserved to priests are his judging and praying with laity in the Sacrament of Repentance (or Confession), and the celebration of the Divine Liturgy (or Eucharist). The presence and ministry of a priest is required for a parish to function normally.
Some branches of Christianity, often within Protestantism, do not use the term "priest" to describe the individual who has an officiating role, because they do not believe in the idea of a sacrificial mass; instead, terms like "Minister" or "Pastor" are often used in its place.
Quakerism does not grant a special priestly role to any individual, partly because Quakers do not practice any special sacraments that require priestly mediation, and partly because they believe that the priesthood of all believers grants the potential of a spiritual and ministerial role to all individuals within the denomination, regardless of sex or status within the faith.
Roman Catholic, Anglican, many American Episcopalian, and some Lutheran priests and pastors wear the stiff white clerical collar (informally "dog collar") around the neck during duties at church or in hospital.