Source : Webster's Revised Unabridged Dictionary (1913)

Encephalitis \En*ceph`a*li"tis\, n. [NL., from Gr. ? the brain +
   -itis.] (Med.)
   Inflammation of the brain. -- {En`ceph*a*lit"ic}, a.

Source : WordNet®

encephalitis
     n : inflammation of the brain usually caused by a virus;
         symptoms include headache and neck pain and drowsiness
         and nausea and fever (`phrenitis' is no longer in
         scientific use) [syn: {cephalitis}, {phrenitis}]
     [also: {encephalitides} (pl)]