1the process of releasing, and thereby providing relief from, strong or repressed emotions:music is a means of catharsis for them
2 Medicine, rare purgation.
early 19th century(in catharsis (sense 2)): from Greek katharsis, from kathairein 'cleanse', from katharos 'pure'. The notion of ‘release’ through drama (catharsis (sense 1)) derives from Aristotle's Poetics
catharsis in other Oxford dictionaries
Definition of catharsis in the US English dictionary