Crusade (book) definition

noun

(1) 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"

(2) 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

verb

(3) Go on a crusade; fight a holy war