Source : Webster's Revised Unabridged Dictionary (1913)

Diarrhea \Di`ar*rhe"a\, Diarrhoea \Di`ar*rh[oe]"a\, n. [L.
   diarrhoea, Gr. ?, fr. ? to flow through; ? + ? to flow; akin
   to E. stream. See {Stream}.] (Med.)
   A morbidly frequent and profuse discharge of loose or fluid
   evacuations from the intestines, without tenesmus; a purging
   or looseness of the bowels; a flux.

Source : WordNet®

diarrhoea
     n : frequent and watery bowel movements; can be a symptom of
         infection or food poisoning or colitis or a
         gastrointestinal tumor [syn: {diarrhea}, {looseness of
         the bowels}]