From Greek 'katharsis' (κάθαρσις, cleansing), from 'katharos' (pure). Aristotle coined the literary sense in his Poetics: tragedy purges the audience of pity and fear. The same root gives us 'cathartic,' the name 'Catherine' (the pure one), and the medieval 'Cathars' who called themselves the pure.
The process of releasing, and thereby providing relief from, strong or repressed emotions; in medicine, purgation of the body.
From Greek 'katharsis' (κάθαρσις), meaning 'cleansing, purging, purification,' from 'kathairein' (καθαίρειν, 'to cleanse, purge'), from 'katharos' (καθαρός, 'pure, clean'). Aristotle used the term in his Poetics (c. 335 BCE) to describe the emotional purging that audiences experience through watching tragedy — the release of pity and fear that leaves them spiritually lighter. The medical sense (bodily purgation) predates Aristotle: Hippocratic physicians used 'katharsis' for the expulsion of harmful substances from the body. The word entered English in the early 19th century, primarily through Aristotle's influence
The name 'Catherine' derives from the same Greek root 'katharos' (pure) — Katherine the Great and your emotional catharsis share an etymology of cleanliness. The medieval Cathars, a Christian sect persecuted as heretics, named themselves 'the pure ones' from the same word. Even 'catheter' connects: Greek 'katheter' meant 'something let down into' — from 'kata' (down) + 'hienai' (to send), a different compound but the same family of medical Greek.