Thai n 1: a native or inhabitant of Thailand [syn: {Tai}, {Siamese}] 2: a branch of the Tai languages [syn: {Siamese}, {Central Thai}] Thai adj 1: of or relating to or characteristic of Thailand or its people; "Siamese kings"; "different Thai tribes live in the north" [syn: {Tai}, {Siamese}] 2: of or relating to the languages of the Thai people; "Thai tones" [syn: {Tai}, {Siamese}] 3: of or relating to Thailand; "the Thai border with Laos" [syn: {Tai}, {Siamese}]