Agent Orange: A chemical defoliant, prevented VC and NVA soldiers from taking advantage of dense jungle cover, especially along rivers, used to defoliate approximately one-seventh of the vegetation in South Vietnam

ARVN: The Army of the Republic of Vietnam (i.e., the South Vietnamese Army), allied with U.S. forces in the Vietnam conflict, widely criticized by U.S. forces for incompetence, corruption, and low morale

Bao Dai: Figurehead emperor of Indochina, later of South Vietnam, supported by France, had little political power

Charlie: Commonly used nickname for Viet Cong forces, from the radio call sign for "VC": "victor charlie"

Cu Chi: Extensive tunnel complex near Saigon, housed thousands of VC and NVA soldiers; never destroyed, despite being deep in South Vietnamese territory

Diem, Ngo Dinh: Long-time president of South Vietnam; overthrew Bao Dai in October, 1955 (following an election in which Diem received 98.2% of the vote, including almost all of the 605,000 ballots cast by Saigon's 405,000 registered voters); proclaimed the creation of the Republic of Vietnam, appointed himself as President; a corrupt and unpopular ruler, he ruthlessly suppressed protests by students and Buddhist monks; overthrown (with CIA approval) and murdered by dissident South Vietnamese army officers in November, 1963; this led to much greater political instability in South Vietnam

Dien Bien Phu: A battle in northern Indochina in 1954 that pitted French soldiers against Viet Minh troops, the French garrison was surrounded and France begged for U.S. air support, but President Eisenhower refused; the subsequent French defeat made it impossible for France to continue to occupy Indochina, this led to the Geneva Accords

DMZ: The Demilitarized Zone, roughly paralleling the 17th parallel, that separated North and South Vietnam.  U.S. troops never crossed the DMZ, and thus never invaded North Vietnam

French Indochina: See "Indochina"

Geneva Accords: A peace conference held at Geneva, Switzerland in 1954, following the French defeat at Dien Bien Phu; the United States was not a direct participant in the peace talks between France and the Viet Minh, but certainly influenced the outcome; French Indochina was divided into four regions (North Vietnam, South Vietnam, Laos, and Cambodia), Vietnam itself was divided along the 17th parallel, with the promise of free elections within two years to reunify the country, these elections were never held, since the United States concluded that Ho Chi Minh would win easily and thus reunify Vietnam under North Vietnamese communist leadership

Gook: Derogatory name for Viet Cong soldiers

Hanoi: The capital of the Peoples' Republic of Vietnam (North Vietnam)

Ho Chi Minh: President of North Vietnam, gained fame by attacking the French colonizers before and after World War II, and the Japanese during World War II, a nationalist first and a communist second, guiding light of North Vietnam's efforts to "liberate" Vietnamese soil from foreign (i.e., U.S.) occupation, died in September, 1969

Ho Chi Minh Trail: An extensive network of roads and trail leading from North Vietnam through neighboring Laos and Cambodia, and then into South Vietnam, allowed North Vietnam to funnel supplies and reinforcements to NVA and VC forces operating in South Vietnam

Hot LZ: A landing zone under enemy fire

Howitzer: A long-range artillery piece used by U.S. troops

Huey: A medium-sized all-purpose helicopter, used to insert and remove troops, evacuate wounded, for general transport, etc.

Indochina: The French name for a region in Southeast Asia consisting on the modern countries of Vietnam, Laos, and Cambodia; this region was conquered and colonized by many outsiders, including the Chinese, the French, and the Japanese; by the early 20th century, French colonists exploited native Vietnamese labor to cultivate rubber, rice, and tea; French troops maintained order and crushed potential revolts, while a small core of French bureaucrats governed the country, assisted by native Vietnamese civil service officials

LRRP: ("Lurps"): Long-Range Reconnaissance Patrols, small groups (typically six) of highly trained U.S. soldiers, often working behind enemy lines

LZ: Landing Zone for helicopters

MACV: Military Assistance Command, Vietnam, the administrative entity responsible for organizing and carrying out U.S. military operations in Vietnam

Napalm: Jellied gasoline, dropped from attack jets, incinerated anything it hit, produced horrific burns in survivors

Phosphorus: White phosphorus bombs, very destructive, also produced horrific burn injuries

Republic of Vietnam: South Vietnam, allied with the United States

Saigon: The capital of South Vietnam, not directly attacked by NVA forces until after the U.S. withdrawal, but was subject to small-scale attacks by well-organized VC guerilla troops on many occasions

Slope: Derogatory name for Viet Cong soldiers

Tet: The Vietnamese lunar New Year; in January and February, 1968 NVA and VC forces broke a truce and attacked U.S. and ARVN forces throughout South Vietnam, the Tet Offensive was a pivotal event in the conflict

VC: Viet Cong guerilla forces operating throughout South Vietnam, allied with NVA forces against U.S. and ARVN soldiers

Viet Cong: See "VC"

Viet Minh: The predecessor group to the Viet Cong, led by Ho Chi Minh, operated against the French and Japanese occupation forces, allied with the United States during World War II

Vo Nguyen Giap: General in the North Vietnamese Army and military adviser to Ho Chi Minh, chief architect of North Vietnam's military strategy against the United States

Westmoreland: General William Westmoreland, U.S. commander of MACV