The Kingdom of Thailand is an independent country that lies in the heart of Southeast Asia. It is bordered to the north by Laos and Myanmar, to the east by Laos and Cambodia, to the south by the Gulf of Thailand and Malaysia, and to the west by the Andaman Sea and Myanmar. By the maritime boundary, the country is bordered to the southeast by Vietnam in the Gulf of Thailand, to the southwest by Indonesia and India in the Andaman Sea. The capital and largest city of Thailand is Bangkok. It is also the country's center of political, commercial, industrial and cultural activities. Bangkok is known in Thai as "Krung Thep Mahanakorn," or, more colloquially, "Krung Thep", meaning "City of Angels". Thailand is the world's 51st-largest country in terms of total area, roughly equal in size to Spain, with a surface area of approximately 513,000 km2 (198,000 sq mi), and the 20th most-populous country, with approximately 63 million people. About 75% of the population is ethnically Thais, 14% is of Chinese origin, and 3% is ethnically Malay, the rest belong to minority groups including

Thailand is one of the most devoutly Buddhist countries in the world. The national religion is Theravada Buddhism which is practiced by more than 95% of all Thais. The cultures and traditions in Thailand are significantly influenced by those of India, China and many western countries.

Thailand is a constitutional monarchy with King Bhumibol Adulyadej, the ninth king of the House of Chakri, as the ruling monarch. The King has reigned for more than half a century, making him the longest reigning Thai monarch and the longest reigning current monarch in the world. The King is recognized as the Head of State, the Head of the Armed Forces, the Upholder of the Buddhist religion, and Defender of the Faith. Thailand is the only country in Southeast Asia that has never been ruled by a European power. However, during the Second World War, and while claiming neutrality, Thailand was occupied by the armed forces of the Empire of Japan who built the infamous 'Death Railway' using captured Allied Prisoners of War and slave Asian labourers.

The country's official name was Siam until June 23, 1939, when it was changed to Thailand. It was renamed Siam from 1945 to May 11, 1949, after which it was again renamed Thailand. Also spelled Siem, Syâm or Syâma, it has been identified with the Sanskrit Syâma, dark or brown. But the names Shan and A-hom seem to be variants of the same word, and Syâma is possibly not its origin but a learned and artificial distortion.

The word Thai is not, as commonly believed, derived from the word Tai meaning "free" in the Thai language; it is, however, the name of an ethnic group from the central plains (the Thai people).[citation needed] A famous Thai scholar argued that Tai 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" for people. The phrase "Land of the free" is derived from the fact that the Thai are proud of the fact that Thailand is the only country in Southeast Asia never colonized by Europe.

Ratcha Anachak Thai means "Kingdom of Thailand" or "Kingdom of Thai." Etymologically, its components are: -Ratcha- (from Sanskrit raja, meaning "king, royal, realm,") ; -ana- (from Pali a?a, "authority, command, power," itself from Sanskrit ajña, same meaning) -chak (from Sanskrit cakra or cakra? meaning "wheel", a symbol of power and rule).