An emir is a prince, head of state, tribal chieftain, or governor in the Middle East or Central Asia. Also, it serves as an honorific title for the descendants of the Prophet Muhammad. "Emir" shows up in the name of the U.A.E., the United Arab Emirates, a confederation of seven Arab states on the Persian Gulf.
The word emir comes from the Arabic amir, meaning "commander," from the root amara -- "to command." An interesting side note: the English word "admiral" for a naval officer of the highest rank also comes from this root. It was introduced into Europe via Italy in the 12th or 13th century.
"In 1842, Nasrullah Khan, the Emir of Bukhara, executed Arthur Conolly and Charles Stoddart on charges of spying for Great Britain."