any of the more or less continuous military expeditions in the 11th to 13th centuries when Christian powers of Europe tried to recapture the Holy Land from the Muslims
go on a crusade; fight a holy war
exert oneself continuously, vigorously, or obtrusively to gain an end or engage in a crusade for a certain cause or person; be an advocate for; "The liberal party pushed for reforms"; "She is crusading for women's rights"; "The Dean is pushing for his favorite candidate"
an overland journey by hunters (especially in Africa)
a series of actions advancing a principle or tending toward a particular end; "he supported populist campaigns"; "they worked in the cause of world peace"; "the team was ready for a drive toward the pennant"; "the movement to end slavery"; "contributed to the war effort"
several related operations aimed at achieving a particular goal (usually within geographical and temporal constraints)
go on a campaign; go off to war
run, stand, or compete for an office or a position; "Who's running for treasurer this year?"
a concerted campaign to end something that is injurious; "the war on poverty"; "the war against crime"
the waging of armed conflict against an enemy; "thousands of people were killed in the war"
an active struggle between competing entities; "a price war"; "a war of wits"; "diplomatic warfare"
a legal state created by a declaration of war and ended by official declaration during which the international rules of war apply; "war was declared in November but actual fighting did not begin until the following spring"