priest – n. a person who has the authority to lead or perform ceremonies in some religions and especially in some Christian religions
diocese – n. the area that is controlled by a bishop
ordain – v. the official act or process of making someone a priest
apostles – n any one of the 12 men chosen by Jesus Christ to spread the Christian religion
deacon – n. an official in some Christian churches whose rank is just below a priest
Mass – n. a Christian ceremony especially in the Roman Catholic Church in which people eat bread and drink wine representing the body and blood of Jesus Christ