An archbishop or metropolitan bishop is a bishop whose religious jurisdiction extends over a geographical area that is larger or contains a larger population than that of most bishops. For example, the Catholic bishop of San Francisco is called an "archbishop" due to the size and significance of his jurisdiction.
Some archbishops have jurisdiction over entire nations. This includes Jean-Claude Hollerich who is in command of the Archdiocese of Luxembourg. 
- ↑ http://www.ewtn.com/vexperts/showmessage.asp?number=576555
- ↑ http://catholicstraightanswers.com/what-is-the-difference-between-a-diocese-and-an-archdiocese-what-about-a-bishop-and-an-archbishop
- ↑ http://www.gcatholic.org/dioceses/diocese/luxe0.htm
- ↑ One or more dioceses may also be grouped together with an archdiocese into an ecclesiastical province.