Arch-dioceses are a group of dioceses that are grouped together under the authority of an archbishop. There are several synonyms for the word "arch-dioceses" including archbishopric, archiepiscopate, metropolitanate, and metropolis. An archbishopric is a territory or jurisdiction under the authority of an archbishop. The term archiepiscopate refers to the office of an archbishop, while the metropolitanate refers to the territorial jurisdiction of a metropolitan bishop. The word metropolis is another synonym for arch-dioceses and is commonly used to refer to a large city or urban area that is the center of government or commerce. All these terms refer to the same concept of a group of dioceses under the authority of an archbishop.