However, at different times the empire ruled large parts of what is now Thailand, Laos, and Vietnam.
The name "Cambodia" derives from the French Cambodge, which comes from the Khmer word Kâmpuchea, meaning "born of Kambu." During the socialist regimes of Democratic Kampuchea (DK) (1975–1979) and the People's Republic of Kampuchea (PRK) (1979–1989), the country was known internationally as Kampuchea, but more recent governments have returned to using Cambodia, and the official name in English is now the Kingdom of Cambodia.
Khmer as a noun or adjective can refer to the Cambodian language, people, or culture and thus suggests an ethnic and linguistic identity more than a political entity.
It is generally accepted that if Cambodia had not been colonized by France, it would have been swallowed by its neighbors. True national identity was created during the French colonial presence.
The French fixed boundaries, systematized government and ecclesiastical bureaucracies, promoted the empire as a national symbol, encouraged an increasingly elaborate ceremonial role for the king, and introduced secular education. There are significant populations of ethnic Khmer in Thailand and Vietnam.
Large numbers of the Cambodian refugees who fled to camps in Thailand during the DK period and the early PRK period resettled in the United States, France, Australia, and New Zealand.
The largest ethnic minority population is Vietnamese, whose numbers range between 500,000 and a million.
The Khmer in Thailand are well integrated into the Thai state, with few significant links to Cambodia.
The Khmer in southern Vietnam, called Khmer Kraom, have historically had much stronger ties to Cambodia proper, and several important Cambodian political leaders have been Khmer Kraom.
From 1970 to 1975, the country was known as the Khmer Republic (KR). Cambodia lies between Thailand and Vietnam in mainland southeast Asia, with a smaller stretch of the northern border adjoining Laos.
The most central region culturally and economically is the lowland flood plain of the Mekong River and Tonle Sap Lake.
In the fifteenth century, the capital was moved to the area of the intersection of the Sap and Mekong rivers, near present-day Phnom Penh, perhaps to enhance trade.