An Arabian military commander, independent chieftain, or ruler of a province; also, an honorary title given to the descendants of Mohammed, in the line of his daughter Fatima; among the Turks, likewise, a title of dignity, given to certain high officials.
ruler, military commander or governor
alt. Amir - Arab term describing a chief who was invested with the command. This title was originally at the origin by the army chiefs of the first Caliphs , who kept it while becoming governor of provinces. It is today the official title of the Heads of States of several Gulf countries: Kuwait, Bahrain, Qatar and the seven federate States of the United Arab Emirates. The title of Emir is also given to the male members of the Saudi royal family as well as to the governors of provinces in Saudi Arabia.
A prince or ruler of an Islamic territory, or emirate. (Fine, John V.A. Jr. The Late Medieval Balkans, 622)