a Tai (Dai) people related to the Shan of Burma and the Lao of Laos, originally from southern China, which settled in the Menam (Mae Nam) river basin; an alliance of Thai princes resulted in the foundation of the kingdom of Sukothai in around 1220. Sukothai was the progenitor of the later Kingdoms of Siam and Thailand.
a branch of the Tai languages
of or relating to or characteristic of Thailand or its people; "Siamese kings"; "different Thai tribes live in the north"
of or relating to the languages of the Thai people; "Thai tones"
of or relating to Thailand; "the Thai border with Laos"