A Quick and Simple Dictionary

Crusade

1. Proper noun.  One of a series of ostensibly religious campaigns by Christian forces from the 11th to the 13th century, mostly to capture the Holy Land from the Muslims who occupied it.
2. Noun.  Any of the military expedition undertaken by the Christians of Europe in the 11th to 13th centuries to reconquest the Levant from the Muslims .
3. Noun.  (figuratively) A grand concerted effort toward some purportedly worthy cause.
4. Verb.  To make a grand concerted effort toward some purportedly worthy cause.