Noyan

Noyan was a Central Asian title of authority which was used to refer to civil-military leaders of noble ancestry in the Central Asian Turkic Khanates with origins in Noyon, which was used as a title of authority in the Chagatai Khanate of the Mongol Empire. In modern times, Noyan is used as a given name or surname in Turkey and throughout Central Asia meaning "the commander-in-chief", "the lord", "the protector".
Mongol Empire.
Initially, Noyon was a term for the chief of a Mongolian nomad community who, in times of war, had the function as a military commander in the army of Genghis Khan. The term "Noyon" applied to leaders of "Tumens" and "Mingghans", social-military units of 10,000 and 1,000 households respectively, each of them with one recruitable soldier. During conquests, "Noyons" used to receive territories for administration and they effectively became aristocracy, into the 20th century. "Noyons" were above the ordinary Mongols in social rank but below the descendants of Genghis Khan. They were sometimes called emir or bey in the Ulus of Jochi, the Ilkhanate and the Chagatai Khanate while historical records of the Yuan dynasty of China gave the equivalent as "guanren" (官人), since their main task was waging warfare. 
Usually, "Noyon" followed the name of a person similar to the usage of the title "Khan" or "Bey".
Qing dynasty.
The Qing dynasty of China, which ruled Mongolia from 1694 to 1911, entrusted rule in Mongolia to the descendants of Genghis Khan, who were also called "Noyon". The term "Noyon" in this epoch acquired the connotation of nobleman, since Mongolia was mostly at peace. After 1921 the word "Darga" (boss) replaced the aristocratic "Noyon" as the term for officials.
Modern Mongolia.
In modern Mongolian, the word is used as a form of address similar to "Mister" or "Monsieur".