A lot vs. Alot: 9 Grammatical Pitfalls
1803, "bodily purging," from Latinized form of Greek katharsis "purging, cleansing," from stem of kathairein "to purify, purge," from katharos "pure, clear of dirt, clean, spotless; open, free; clear of shame or guilt; purified" (with most of the extended senses now found in Modern English clear, clean, pure), of unknown origin. Originally medical in English; of emotions from 1872; psychotherapy sense first recorded 1909, in Brill's translation of Freud.
catharsis ca·thar·sis (kə-thär'sĭs)
n. pl. ca·thar·ses (-sēz)
A psychological technique used to relieve tension and anxiety by bringing repressed feelings and fears to consciousness.
The therapeutic result of this process; abreaction.