The country’s official name was Siam (สยาม) until 23 June 1939, when it was changed to Thailand; it was renamed Siam between 1945 and 11 May 1949, after which the name Thailand was once again adopted. Also spelled Siem, Syâm or Syâma, it has been identified with the Sanskrit Śyâma, dark or brown. But the names Shan and A-hom seem to be variants of the same word and Śyâma is possibly not its origin but a learned and artificial distortion.
The word Thai (ไทย) is not, as commonly believed, derived from the word Tai (ไท) meaning “free” in the Thai language; it is, however, the name of an ethnic group from the central plains (the Thai people). A famous Thai scholar argued that Tai (ไท) simply means “people” or “human being” since his investigation shows that in some rural areas the word “Tai” was used instead of the usual Thai word “khon” (คน) for people. However that may be, the locals seem to have also accepted the alternative meaning and will verbally state that it means “Land of the free.”