What is "beylerbey"

n. An Ottoman administrative title.

Beylerbey or Beylerbeyi (; " Bey of Beys", meaning "the Commander of Commanders" or "the Lord of Lords"; originally Beglerbeg[i] in older Turkic) was a high rank in the western Islamic world in the late Middle Ages and early modern period, from the Seljuks of Rum and the Ilkhanids to Safavid Persia and the Ottoman Empire. Initially designating a commander-in-chief, it eventually came to be held by senior provincial governors. In Ottoman usage, where the rank survived the longest, it designated the governors-general of some of the largest and most important provinces, although in later centuries it became devalued into a mere honorific title. Its equivalents in Arabic were amir al-umara, and in Persian, mir-i miran.

The title was also used by the Khans of the Indian (later Pakistani) princely state of Kalat.