The Collaborative International Dictionary of English v.0.48:

Semeiotic \Se`mei*ot"ic\ (s[=e]`m[-e]*[o^]t"[i^]k or
   s[e^]`m[-e]*[o^]t"[i^]k), or Semiotic \Se`mi*ot"ic\, a. [Gr.
   shmeiwtiko`s, fr. shmei^on a mark, a sign.]
   1. Relating to signs or indications; pertaining to the
      language of signs, or to language generally as indicating
      thought.
      [1913 Webster]

   2. (Med.) Of or pertaining to the signs or symptoms of
      diseases.
      [1913 Webster] Semeiotics

The Collaborative International Dictionary of English v.0.48:

Semiotic \Se`mi*ot"ic\, a.
   Same as Semeiotic.
   [1913 Webster]

WordNet (r) 3.0 (2006):

semiotic
    adj 1: of or relating to semiotics; "semiotic analysis" [syn:
           semiotic, semiotical]