high priest

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun Judaism The chief priest of the ancient Levitical priesthood. By tradition this office was restricted to men.
• noun Mormon Church A priest of the Melchizedek order. By tradition this office is restricted to men.
• noun The head or chief proponent, as of a movement or doctrine.

from the GNU version of the Collaborative International Dictionary of English.

• (Eccl.) A chief priest; esp., the head of the Jewish priesthood.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun A clergyman with a higher function than a normal priest.
• noun In the history of the Hebrew Testament (Tanakh), the male person who was responsible for making the annual sacrifice on the Day of Atonement (Yom Kippur). Always a descendant of Aaron the older brother of Moses.
• noun Jesus Christ.
• noun Mormonism The second-lowest office in the Melchizedek priesthood.
• noun A person holding a position of power or influence; an authority in a field of study, doctrine, art or a movement.
• noun Wicca A third degree (sometimes forth degree) male witch in Wicca.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a preeminent authority or major proponent of a movement or doctrine
• noun a senior clergyman and dignitary