**Pastor **is the canonical head of a parish. He is essentially in charge of the parish and is responsible for all decisions. He also has certain canonical rights and cannot be removed, without his consent, for no reason.
Administrator is similar to pastor but has no canonical rights. The Bishop can remove him at any time for any reason and can even limit the extent of the Administrator’s power to make decisions or changes in the parish.
Parochial Vicar is a priest who assists and helps the Pastor or Administrator. He has no canonical authority or power and can be moved by the Bishop for any reason.
Monsignor is an honorary title given to a priest either because he holds an important position in the diocese (i.e. Vicar General, Rector of the seminary, etc.) or as a way to recognize the hard work and dedication of a particular priest. In and of itself it carries no extra power or authority, it is merely a honorary title.
