The use of a clergy title is a sign of respect.
The use of a clergy title is a sign of respect.

When addressing a member of the clergy, it is proper etiquette and a show of respect to use the proper title. The title is an honorific, similar to the more simple Mrs., Miss or Mrs. When a member of the clergy introduces him- or herself to you, the honorific will probably not be used. Instead, the term is used when others address them in person or in writing.

Protestant

The leaders of Protestant churches are generally called ministers and are addressed by the title "Reverend." Thus, a minister named John Smith would be addressed or introduced as "the Reverend John Smith" or "Reverend Smith." If the minister holds a doctorate, the title of doctor is added, so that John Smith would be addressed as "the Reverend Doctor John Smith."

Catholic

The Catholic Church has many occupations that require titles. Priests are addressed as "Father." Nuns are addressed as "Sister," with the Mother Superior addressed as "Reverend Mother." Catholic monks are addressed as "Brother." A Catholic bishop is addressed as "Your Excellency" or "The Most Reverend," followed by his name. A monsignor is addressed as "The Right Reverend," followed by his name.

Other Religions

Mormon leaders are addressed as "Elder" or simply "Mister." Thus, a Mormon missionary named John Smith would be called "Elder Smith" or "Mr. Smith." A female Mormon missionary is called "Sister." A Jewish rabbi should be addressed as "Rabbi." A Jewish cantor is addressed as "Cantor." A Muslim Imam is addressed as "Imam." A Buddhist priest is addressed as "Reverend."

Etiquette

It is proper etiquette to address a member of the clergy with the correct title, even if you are not a follower of the religion. The title is a term of respect. When addressing envelopes, use the clergy title followed the person's first and last name. Formal introductions should also be made this way, often followed by the name of the congregation they preside over.