Semeiotic

Semeiotic is a term used by Charles Sanders Peirce to distinguish his theory of sign relations from other approaches to the same subject matter.

Types of signs
There are three principal ways that a sign can denote its objects. These are usually described as kinds, species, or types of signs, but it needs to be understood that the same thing can be a sign in different ways.

Beginning very roughly, the three main ways of being a sign can be described as follows:


 * An icon is a sign that denotes its objects by virtue of a quality that it shares with its objects.


 * An index is a sign that denotes its objects by virtue of an existential connection that it has with its objects.


 * A symbol is a sign that denotes its objects solely by virtue of the fact that it is interpreted to do so.