noun

1. any of the military expeditions which Christians undertook from the 11th to the end of the 13th cent. to recover the Holy Land from the Muslims
2. a vigorous, concerted action for some cause or idea, or against some abuse

Origin of crusade

; from Spanish cruzada, altered after French croisade, both ; from Medieval Latin cruciata ; from past participle of cruciare, to mark with a cross ; from Classical Latin crux, cross

intransitive verb

crusaded, crusading