The Collaborative International Dictionary of English v.0.48:

Dysentery \Dys"en*ter*y\, n. [L. dysenteria, Gr. ?; dys- ill,
   bad + ?, pl. ?, intestines, fr. 'ento`s within, fr. ? in,
   akin to E. in: cf. F. dysenterie. See Dys, and In.]
   (Med.)
   A disease attended with inflammation and ulceration of the
   colon and rectum, and characterized by griping pains,
   constant desire to evacuate the bowels, and the discharge of
   mucus and blood.
   [1913 Webster]

   Note: When acute, dysentery is usually accompanied with high
         fevers. It occurs epidemically, and is believed to be
         communicable through the medium of the alvine
         discharges.
         [1913 Webster]

WordNet (r) 3.0 (2006):

dysentery
    n 1: an infection of the intestines marked by severe diarrhea