Semiosis (from the Greek: σημείωσις, sēmeíōsis, a derivation of the verb σημειῶ, sēmeiô, "to mark") is any form of activity, conduct, or process that involves signs, including the production of meaning. Briefly – semiosis is sign process. The term was introduced by Charles Sanders Peirce (1839–1914) to describe a process that interprets signs as referring to their objects, as described in his theory of sign relations, or semiotics. Semiosis is triadic and cyclic. Other theories of sign processes are sometimes carried out under the heading of semiology, following on the work of Ferdinand de Saussure (1857–1913).
Peirce was interested primarily in logic, while Saussure was interested primarily in linguistics, which examines the functions and structures of language. However, both of them recognized that there is more to significant representation than language in the narrow sense of speech and writing alone. With this in mind, they developed the idea of semiosis to relate language to other sign systems both human and nonhuman. Today, there is disagreement as to the operating cause and effect. One school of thought argues that language is the semiotic prototype and its study illuminates principles that can be applied to other sign systems. The opposing school argues that there is a metasign system and that language is simply one of many codes for communicating meaning, citing the way in which human infants learn about their environment before they have acquired verbal language. Whichever may be right, a preliminary definition of semiosis is any action or influence for communicating meaning by establishing relationships between signs which are to be interpreted by an audience.