Definition of "catharism" []

• The process of making a surface chemically clean. (noun)

The Century Dictionary (Public Domain)

• "Glen Cook liberally uses European High Middle Ages, blending together: crusades, pope (and antipope), Jews, emperor of the Holy Roman Empire and the King of Spain, Janissaries, ruling noble families of Rome caught in everlasting cloak and dagger games for papacy, corruption of the medieval Catholic Church, catharism and it's centre the Languedoc and last, but not least the Vikings and their pantheon."