noun

1. CRUSADE, a series of actions advancing a principle or tending toward a particular end
2. CRUSADE, 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
3. CRUSADE, any one of the wars that European Christian countries fought against Muslims in Palestine in the 11th, 12th, and 13th centuries
4. CRUSADE, a major effort to change something

verb

1. CRUSADE, go on a crusade; fight a holy war
2. CRUSADE, 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
3. CRUSADE, to take part in a major effort to change something

1. a grassroots crusade for spending more money on our public schools