A cleric; someone (such as a priest) who administers a church (ecclesia) or other religious gathering/group.
A member of the Athenian ecclesia (public legislative assembly).
A member of any ecclesia (church or other assembly).
Any chief figure or leader of a religion.
A bishop of the early Church; now specifically, the Pope.
A member of the most illustrious of the colleges of priests of the Roman religion, the College of Pontiffs; a pontifex.