The Collaborative International Dictionary of English v.0.48:

Cynanche \Cy*nan"che\ (s?-n?n"k?), n. [L., fr. Gr. ????? a dog's
   collar, a bad kind of sore throat. Cf. Quinsy.] (Med.)
   Any disease of the tonsils, throat, or windpipe, attended
   with inflammation, swelling, and difficulty of breathing and
   swallowing.
   [1913 Webster]