Baig, also commonly spelled Beg, or Begh (Persian: بیگ, Bay, Turkish: Bey) was a title of Turko-Mongol origin, which is today used as a surname or middle name to identify lineage. It means Chief or Commander and is common in Pakistan, India, Afghanistan, Bangladesh, Turkey, Iran, Caucasus, Central Asia and Eastern Europe (former Yugoslav) and among their respective diaspora.
The name Baig is derived from the Turkic-Persian word Beg or Bey, which means commander or chief (i.e. military leader.)
Beg was also subsequently used as a military rank in the Ottoman Empire.
It was also used during the Qing dynasty in China. When the Qing dynasty ruled Xinjiang, it permitted the Turkic Begs in the Altishahr region to maintain their previous status, and they administered the area for the Qing as officials. High-ranking Begs were allowed to wear the Queue.
For the Persian use, it is common to see the name Beg added to the Persian suffix of 'zada' (male), 'zadi' (female), which means 'son of' or 'daughter of'. For Example: Mansur Begzada or Noor Begzadi. For the Turkish use, it is most common to see the spelling Beg or Bey utilized. (Sometimes, it is used along with the title "Mirza", similar to the Moghal usage).