Foco

A guerrilla foco is a small cadre of revolutionaries operating in a nation's countryside. This guerrilla organization was popularized by Che Guevara in his book Guerrilla Warfare, which was based on his experiences in the Cuban Revolution. Guevara would go on to argue that a foco was politically necessary for the success of a socialist revolution. Originally Guevara theorized that a foco was only... (Wikipedia)