Tai \Tai\, a. Designating, or pertaining to, the chief linguistic stock of Indo-China, including the peoples of Siamese and Shan speech.

Source: Webster's Revised Unabridged Dictionary (1913)
 

Tai \Tai\, n. A member of one of the tribes of the Tai stock.

The Tais first appeared in history in Yunnan, and from thence they migrated into Upper Burma. The earliest swarms appear to have entered that tract about two thousand years ago, and were small in number. --Census of India, 1901.

Source: Webster's Revised Unabridged Dictionary (1913)