noun, verb, -sad⋅ed, -sad⋅ing.| 1. | (often initial capital letter ) any of the military expeditions undertaken by the Christians of Europe in the 11th, 12th, and 13th centuries for the recovery of the Holy Land from the Muslims. |
| 2. | any war carried on under papal sanction. |
| 3. | any vigorous, aggressive movement for the defense or advancement of an idea, cause, etc.: a crusade against child abuse. |
| 4. | to go on or engage in a crusade. |
cru·sade (krōō-sād') n.
To engage in a crusade. [French croisade and Spanish cruzada, both ultimately from Latin crux, cruc-, cross.] cru·sad'er n. |