Relating to signs or indications; pertaining to the language of signs, or to language generally as indicating thought.

Of or pertaining to the signs or symptoms of diseases.

Although it can be considered as a synonym of Semiotics, the term Semeiotic (or Semeiotics) is often used to refer more narrowly to Charles Sanders Peirce's theory of signs. A crucial characteristic of this specific theory of signs is the idea of the sign being a kind of relation, which Peirce defines as triadic. From this perspective, the sign is considered as a process of semiosis or signifying relation between three elements: the representament, the object, and the interpretant.