\Se`mei*ol"o*gy\, or Semiology \Se`mi*ol"o*gy\, n.
[Gr. shmei^on a mark, a sign + -logy.]
The science or art of signs. Specifically:
(a) (Med.) The science of the signs or symptoms of disease;
    symptomatology.
(b) The art of using signs in signaling.