
The Khmer Rouge is the name that was popularly given to members of the Communist Party of Kampuchea (CPK) and by extension to the regime through which the CPK ruled Cambodia between 1975 and 1979. The name had been coined in the 1960s by Norodom Sihanouk to describe his country's then heterogeneous, communist-led dissidents, with whom he allied after his 1970 overthrow.

The Khmer Rouge period refers to the rule of Pol Pot, Nuon Chea, Ieng Sary, Son Sen, Khieu Samphan and the Communist Party of Kampuchea over Cambodia, which the Khmer Rouge renamed Democratic Kampuchea.

The Ba Chúc massacre was carried out by the Kampuchean Revolutionary Army from April 18 to April 30, 1978 in Ba Chúc, Tri Tôn, An Giang Province, Vietnam. Of those who had lived in Ba Chúc, 3,157 civilians were killed. Only two survived the massacre. In addition, more than 200 people were killed or injured by land mines deployed by the Khmer Rouge upon retreat.
The Cambodian genocide was the systematic persecution and killing of Cambodians by the Khmer Rouge under the leadership of Pol Pot, who radically pushed Cambodia towards communism. It resulted in the deaths of 1.5 to 2 million people from 1975 to 1979, nearly a quarter of Cambodia's 1975 population.
Cambodian genocide denial was the belief expressed by many Western academics that claims of atrocities by the Khmer Rouge government (1975–1979) in Cambodia were much exaggerated. Many scholars of Cambodia and intellectuals opposed to the U.S. involvement in the Vietnam War denied or minimized the human rights abuses of the Khmer Rouge, characterizing contrary reports as "tales told by refugees" and U.S. propaganda. They viewed the assumption of power by the communist Khmer Rouge as a positive development for the people of Cambodia who had been severely impacted by the Vietnam War and the Cambodian Civil War.

The Cambodian–Vietnamese War, known in Vietnam as the Counter-offensive on the Southwestern border, and by Cambodian nationalists as the Vietnamese invasion of Cambodia, was an armed conflict between Democratic Kampuchea, controlled by the Khmer Rouge, and the Socialist Republic of Vietnam. The war began with repeated attacks by the Kampuchean Revolutionary Army on the southwestern border of Vietnam, particularly the Ba Chuc massacre which resulted in the deaths of over 3,000 Vietnamese civilians. On 25 December 1978, Vietnam launched a full-scale invasion of Kampuchea, and subsequently occupied the country and removed the government of the Communist Party of Kampuchea from power.

The Coalition Government of Democratic Kampuchea, renamed to the National Government of Cambodia from 1990, was a coalition government in exile composed of three Cambodian political factions, namely Prince Norodom Sihanouk's FUNCINPEC party, the Party of Democratic Kampuchea and the Khmer People's National Liberation Front (KPNLF) formed in 1982, broadening the de facto deposed Democratic Kampuchea regime. For most of its existence, it was the internationally recognized government of Cambodia.

The Communist Party of Kampuchea, also known as the Khmer Communist Party was a communist party in Cambodia. Its leader was Pol Pot and its followers were generally known as Khmer Rouge. Originally founded in 1951, the party was split into pro-Chinese and pro-Soviet factions, as a result of the Sino–Soviet split. As such, it claimed 30 September 1960 as its founding date, then as the Workers' Party of Kampuchea before being renamed the Communist Party in 1966. The party was underground for most of its existence and took power in the country in April 1975 and established the state known as Democratic Kampuchea. The party lost power in 1979 with the establishment of the People's Republic of Kampuchea by leftists who were dissatisfied by the Pol Pot regime and by the intervention of Vietnamese military forces after a period of mass killing. The party was officially dissolved in 1981, with the Party of Democratic Kampuchea claiming its legacy.

Kampuchea, officially from 5 January 1976 Democratic Kampuchea, also described as the Genocidal Regime, was the Cambodian state under a one-party Marxist-Leninist totalitarian dictatorship that existed between 1975 and 1979. It was controlled by the Khmer Rouge (KR), the name popularly given to the followers of the Communist Party of Kampuchea (CPK), and was founded when KR forces defeated the Khmer Republic of Lon Nol in 1975.

Eastern Zone massacres refers to killings perpetrated by the Khmer Rouge in the Eastern Region of Democratic Kampuchea in 1978 during the Cambodian genocide. They differ from the persecutions and killings of professionals, intellectuals and ethnic minorities which the Khmer Rouge perpetrated in the rest of the country because the killings were result of a purge that occurred within the Khmer Rouge's ranks.

The Royal Government of the National Union of Kampuchea was a government-in-exile of Cambodia, based in Beijing, that was in existence between 1970 and 1976, and was briefly in control of the country starting in 1975.

Khao-I-Dang Holding Center was a Cambodian refugee camp 20 km north of Aranyaprathet in Prachinburi Province of Thailand. The most enduring refugee camp on the Thai-Cambodian border, it was established in late-1979 and administered by the Thai Interior Ministry and the United Nations High Commissioner for Refugees (UNHCR), unlike other camps on the border, which were administered by a coalition made up of UNICEF, the World Food Program, International Committee of the Red Cross (ICRC) (briefly), and after 1982, the United Nations Border Relief Operation (UNBRO).

The killing caves of Phnom Sampeau are a Khmer Rouge execution site on Phnom Sampeau, a hill 7 mi (11 km) southwest of Battambang in western Cambodia. The Khmer Rouge killed their victims on top of the cave at the rim of a daylight shaft or ceiling hole and then threw the dead body into the cave. Men and women were placed in separate caves and clothes in another. There are a number of caves at Phnom Sampeau that have traditionally served as Buddhist temples. Today there is a large glass memorial in the cave next to the skulls and bones and a golden reclining Buddha, that can be reached via a staircase. A memorial, assembled from cyclone fencing and chicken wire contains human bones at the base of the stairway.

The National Army of Democratic Kampuchea (NADK) was a Cambodian guerrilla force. NADK were the armed forces of the Party of Democratic Kampuchea, operating between 1979 and the late 1990s.

Pol Pot was a Cambodian revolutionary and politician who governed Cambodia as the Prime Minister of Democratic Kampuchea between 1975 and 1979. Ideologically a Marxist–Leninist and a Khmer nationalist, he was a leading member of Cambodia's communist movement, the Khmer Rouge, from 1963 until 1997 and served as the General Secretary of the Communist Party of Kampuchea from 1963 to 1981. Under his administration, Cambodia was converted into a one-party communist state governed according to Pol Pot's interpretation of Marxism–Leninism.

The Provisional Government of National Union and National Salvation of Cambodia (PGNUNSC) was an internationally unrecognized and ostensibly provisional government set up by the Khmer Rouge on July 11, 1994, in opposition to the established Kingdom of Cambodia.