Partisan (military) in the context of "Franc-Tireur"

Guerrilla warfare is a type of unconventional warfare in which small groups of irregular military, such as rebels, partisans, paramilitary personnel or armed civilians, which may include children in the military, use ambushes, sabotage, terrorism, raids, petty warfare or hit-and-run tactics in a rebellion, in a violent conflict, in a war or in a civil war to fight against regular military, police or rival insurgent forces.

Although the term "guerrilla warfare" was coined in the context of the Peninsular War in the 19th century, the tactical methods of guerrilla warfare have long been in use. In the 6th century BC, Sun Tzu proposed the use of guerrilla-style tactics in The Art of War. The 3rd century BC Roman general Quintus Fabius Maximus Verrucosus is also credited with inventing many of the tactics of guerrilla warfare through what is today called the Fabian strategy, and in China Peng Yue is also often regarded as the inventor of guerrilla warfare. Guerrilla warfare has been used by various factions throughout history and is particularly associated with revolutionary movements and popular resistance against invading or occupying armies.

Einsatzgruppen (German: [ˈaɪnzatsˌɡʁʊpm̩], lit. 'deployment groups'; also 'task forces') were Schutzstaffel (SS) paramilitary death squads of Nazi Germany that were responsible for mass murder, primarily by shooting, during World War II (1939–1945) in German-occupied Europe. The Einsatzgruppen had an integral role in the implementation of the so-called "Final Solution to the Jewish question" (Die Endlösung der Judenfrage) in territories conquered by Nazi Germany, and were involved in the murder of much of the intelligentsia and cultural elite of Poland, including members of the Catholic priesthood. Almost all of the people they murdered were civilians, beginning with the intelligentsia and swiftly progressing to Soviet political commissars, Jews, and Romani people, as well as actual or alleged partisans throughout Eastern Europe.

Under the direction of Reichsführer-SS Heinrich Himmler and the supervision of SS-Obergruppenführer Reinhard Heydrich, the Einsatzgruppen operated in territories occupied by the Wehrmacht (German armed forces) following the invasion of Poland in September 1939 and the invasion of the Soviet Union in June 1941. The Einsatzgruppen worked hand-in-hand with the Order Police battalions on the Eastern Front to carry out operations ranging from the murder of a few people to operations which lasted over two or more days, such as the massacre at Babi Yar (with 33,771 Jews murdered in two days), and the Rumbula massacre (with about 25,000 Jews murdered in two days of shooting). As ordered by Nazi leader Adolf Hitler, the Wehrmacht cooperated with the Einsatzgruppen, providing logistical support for their operations, and participated in the mass murders. Historian Raul Hilberg estimates that between 1941 and 1945 the Einsatzgruppen, related agencies, and foreign auxiliary personnel murdered more than two million people, including 1.3 million of the 5.5 to 6 million Jews murdered during the Holocaust.

The 15th Army Group was an army group in World War II, composed of the British Eighth Army and initially the Seventh United States Army (1943), replaced by the Fifth United States Army (from January 1944), which apart from units from across the British Empire and United States, also had entire units from other allied countries/regions, including: one corps from Free France and one from Poland; one division from Brazil; multiple separate brigades of Italians and Greeks; plus support to, and from, local Italian partisans. It operated in the Italian Campaign from 1943 to 1945.

The subsequent Nuremberg trials (also Nuremberg Military Tribunals; 1946–1949) were twelve military tribunals for war crimes committed by the leaders of Nazi Germany (1933–1945). The Nuremberg Military Tribunals occurred after the Nuremberg trials, held by the International Military Tribunal, which concluded in October 1946. The subsequent Nuremberg trials were held by U.S. military courts and dealt with the cases of crimes against humanity committed by the business community of Nazi Germany, specifically the crimes of using slave labor and plundering occupied countries, and the war-crime cases of Wehrmacht officers who committed atrocities against Allied prisoners of war, partisans, and guerrillas.

An ambush is a surprise attack carried out by combatants waiting in a concealed (and typically well-defiladed) position against an approaching enemy individual or group. The concealed position itself or the concealed person(s) may also be called an "ambush", and the chosen area to carry out the ambush is known as the kill zone or the trap.

The term "ambush" is also used in animal behavior studies to describe the predation strategy of some carnivores using stealth and deception (i.e. ambush predators), in sociology to describe aggressive journalistic practices (i.e. ambush journalism), and in economics to describe some marketing strategies (i.e. ambush marketing), all of which involve an element of surprise upon the recipients.