Source : Webster's Revised Unabridged Dictionary (1913)

Peritonitis \Per`i*to*ni"tis\, n. [NL. See {Peritoneum}, and
   {-itis}.] (Med.)
   Inflammation of the peritoneum.

Source : WordNet®

peritonitis
     n : inflammation of the peritoneum [syn: {peritoneal
         inflammation}]