Definition: Archdiocese (nominative) - A bishopric, or a diocesan ecclesiastical province, that has its own capital city and jurisdiction within the territory of that diocese. Examples: Catholic Archdiocese of Chicago, Latin American Archdiocese in Peru, etc. Definition: The title given to the bishop who serves as the spiritual authority for all the members of the church within a diocese or ecclesiastical province (i.e., the cathedral archbishop, the metropolitan archbishop, and so on) and is responsible for overseeing the spiritual and social activities within the diocese.