a member of the clergy and a spiritual leader of the Christian Church
The Reverend is an appropriate title to precede the full name of a priest or deacon. The Right Reverend is used for a bishop.
An adjective used in formally addressing a member of the clergy. The term is incorrectly used as a noun title (like bishop or sister) to refer to a member of the clergy. "The Very Reverend" indicates a dean of a deanery, a seminary, or a cathedral. "The Right Reverend" indicates a bishop, an abbot or abbess, or other prelate. "The Most Reverend" indicates an archbishop or primate.
The Reverend is an appropriate title to precede the full name of a deacon or priest. The Right Reverend is appropriate for a bishop. Reverend is an adjective, not a noun. The article the should always precede it.
The Reverend is an honorary prefix to the names of many Christian clergy and ministers. It is correctly called a style rather than a title or term of address. "The Reverend" is sometimes also used by leaders in non-Christian religions such as Buddhism or the Universal Life Church.