military campaign, campaign - several related operations aimed at achieving a particular goal (usually within geographical and temporal constraints)

Crusade - any of the more or less continuous military expeditions in the 11-13th centuries when Christian powers of Europe tried to recapture the Holy Land from the Muslims

armed forces, armed services, military, military machine, war machine - the military forces of a nation; "their military is the largest in the region"; "the military machine is the same one we faced in 1991 but now it is weaker"