The Collaborative International Dictionary of English v.0.48:

Sematology \Sem`a*tol"o*gy\, n. [Gr. sh^ma, sh`matos, sign +
   -logy.]
   The doctrine of signs as the expression of thought or
   reasoning; the science of indicating thought by signs.
   --Smart.

   Syn: semantics. [1913 Webster]