GUERRILLA

A 'guerrilla' (loaned from the Spanish ''guerrilla'', a diminutive form of ''guerra'', war) is a body of fighters engaging in mobile asymmetric irregular warfare, which is now known as 'guerrilla warfare'. A member of a guerrilla is called a ''guerrillero'' or guerrilla fighter.
The correct Spanish spelling is guerrilla, but in English both guerrilla and the less common spelling guerilla are acceptable.
A 'counter-guerrilla' is a guerrilla force the objective of which is the defeat of another guerilla force.
The word guerrilla was first used in Spain during the Peninsular war against the French, and referred to an undefined body of irregular fighters or even all irregular fighters in Spain. The word was soon defined officially by the provisional Spanish government, which defined a guerrilla as a unit of about fifty men, four guerrillas forming a larger unit called a ''cuadrilla''. (''Cuadrilla'' is a diminutive of ''cuadro'', square). However, in practice, guerrillas ranged from a handful of men to over one hundred and could be independent of any larger unit. The French eventually recruited a counter-guerrilla from Spaniards who would fight for them, but the French had little support in Spain and the counter-guerrilla could only recruit from a limited number of criminals and outcasts and had little success.
The varied use of the term "guerilla" continues today, and guerrilla can refer to the entire force of guerrilla fighters of a given conflict, or to a smaller unit: For instance the Colombian guerrilla consists of several completely separate and independent forces, of which one, the FARC guerrilla, uses a specific unit called a guerrilla (two twelve-man squads).