Semiotics, the study of signs or sign system, applies to any kind of signs, not just words (as in semantics).
John Locke first coined the term in 1690 in An essay concerning human understanding.
Charles Sanders Peirce (1839-1914), founder of the philosophical school of pragmatism, invented semiotics as a discipline, terming it ''semeiotic."
Ferdinand de Saussure (1857-1913), the "father" of modern linguistics, invented, at about the same time as Peirce, a subject he called "semiology."
Charles W. Morris (1901-1979) achieved recognition for his Foundations of the Theory of Signs.
Umberto Eco made a wider audience aware of semiotics by various publications, most notably A Theory of Semiotics. Eco explicitly acknowledges Peirce's importance.
Medical Semiotics specifically studies the interpretation of patients' description of their symptoms, and has particular importance for the understanding of how patients describe pain or other symptoms which a physician cannot experience or measure directly.
Literary Semiotics applies the theory of signs (and also communication and information theory) to the interpretation of literary works. Literary semioticians often have an interest in the attempt to apply the tools and techniques of the hard sciences, such as mathematical formulae and computer analysis of texts, to literary criticism
Others, like the French critic, Roland Barthes, and many Marxistss, employ semiotic techniques as a tool of political and social criticism and satire. Pop Culture artifacts have become frequent targets of the semiotic approach, as for example when Barthes deconstructed tag-team wrestling.