A gendarmerie (ʒɒnˈdɑːrməri,_ʒɒ̃-) is a military force with law enforcement duties among the civilian population. The term gendarme (ˈʒɒndɑːrm) is derived from the medieval French expression gens d'armes, which translates to "men-at-arms" (armed people), or "rural police". In France and some Francophone nations, the gendarmerie is a branch of the armed forces that is responsible for internal security in parts of the territory (primarily in rural areas and small towns in the case of France), with additional duties as military police for the armed forces. It was introduced to several other Western European countries during the Napoleonic conquests. In the mid-twentieth century, a number of former French mandates and colonial possessions (such as Lebanon, Syria, the Ivory Coast and the Republic of the Congo) adopted a gendarmerie after independence. A similar concept exists in Eastern Europe in the form of Internal Troops, which are present in many countries of the former Soviet Union and its former allied countries.
Some of the more prominent modern gendarmerie organizations include the French National Gendarmerie, Spanish Civil Guard, the Romanian Jandarmeria, Algerian National Gendarmerie, Argentine National Gendarmerie, Italian Carabinieri, Royal Netherlands Marechaussee, the Royal Moroccan Gendarmerie, the Portuguese National Republican Guard, Mexican National Guard, Serbian Gendarmery, Tunisian National Guard, Turkish Gendarmerie, and the Royal Gendarmerie of Cambodia.
The word gendarme is a singular extracted from Old French gens d'armes (ʒɑ̃ d‿ aʁm), meaning "men-at-arms". From the Late Middle Ages to the Early Modern period, the term referred to a heavily armoured cavalryman of noble birth, primarily serving in the French army. The word gained policing connotations only during the French Revolution, when the Maréchaussée of the Ancien Régime was renamed to Gendarmerie.
Historically, the spelling in English was gendarmery, but now the French spelling gendarmerie is more common.