Source : Webster's Revised Unabridged Dictionary (1913)

Catharsis \Ca*thar"sis\, n. (Psychotherapy)
   The process of relieving an abnormal excitement by
   re["e]stablishing the association of the emotion with the
   memory or idea of the event that first caused it, and of
   eliminating it by complete expression (called the
   abreaction).

Catharsis \Ca*thar"sis\, n. [NL., fr. Gr. ?. See {Cathartic}.]
   (Med.)
   A natural or artificial purgation of any passage, as of the
   mouth, bowels, etc.

Source : WordNet®

catharsis
     n 1: (psychoanalysis) purging of emotional tensions [syn: {katharsis},
           {abreaction}]
     2: purging the body by the use of a cathartic to stimulate
        evacuation of the bowels [syn: {katharsis}, {purgation}]