An icon is a sign that represents its object by resemblance. The representamen shares some quality or structural feature with the thing it stands for — a portrait resembles the person depicted, a map resembles the territory, a diagram resembles the structure it represents.
Peirce distinguished three subtypes of icon (Peirce, 1931–1958):
- Image: resembles the object in simple qualities (a photograph, an onomatopoeia)
- Diagram: resembles the object in relational structure (a flowchart, a mathematical graph)
- Metaphor: represents one thing by its resemblance to another in some respect
Iconic signs are never purely iconic — a map uses conventional markings (symbols) and is produced through a causal process (indexical). The classification identifies which aspect of the sign relation predominates, not which is exclusively present (Chandler, 2007).
Related terms
- index — a sign connected to its object by causal or spatial relation
- symbol — a sign connected to its object by convention
- sign — the triadic relation in which icon is one type
Source: Peirce, Charles Sanders. Collected Papers. Harvard University Press, 1931–1958.
Chandler, D. (2007). Semiotics: The Basics (2nd ed.). Routledge.
Peirce, C. S. (1931–1958). Collected Papers of Charles Sanders Peirce (C. Hartshorne & P. Weiss, Eds.). Harvard University Press.