1. Historical:
* A medieval military expedition: This is the most common meaning. It refers to the religious wars launched by European Christians between the 11th and 13th centuries to reclaim the Holy Land from the Muslims. The Crusades were a series of campaigns with various objectives, but the primary goal was to liberate Jerusalem and other holy sites from Islamic control.
* Any expedition undertaken to promote a cause: While less common, the term "crusade" can be used figuratively to refer to any campaign aimed at achieving a specific goal, often with a moral or religious undertone.
2. Figurative:
* A vigorous campaign: It can describe any organized effort or movement aimed at achieving a specific social or political goal.
* A strong advocacy: It can also refer to a passionate and committed effort to promote a particular belief or cause.
Examples:
* Historical: "The First Crusade was launched in 1095."
* Figurative: "They're on a crusade to ban plastic bags."
* Figurative: "He launched a crusade against corruption."
It's important to note that the term "crusade" can be controversial because of its historical association with religious violence. When used in a figurative sense, it often carries a strong connotation of righteousness and conviction, which can be seen as both positive and negative depending on the context.