The Collaborative International Dictionary of English v.0.48:

Synochus \Syn"o*chus\, n. [NL., from Gr. ? joined together.]
   (Med.)
   A continuous fever. [Obs.]
   [1913 Webster]

   Note: Synocha and synochus were used as epithets of two
         distinct types of fever, but in different senses at
         different periods. The same disease is placed under
         synocha by one author, under synochus by another.
         --Quain.
         [1913 Webster]