Announcing a revolutionary change in the study of language, which had been hitherto philological, Saussure with his Course in General Linguistics (1916), introduced Structural Linguistics, which considers language as a system of signs constructed by cultural conventions. Constituting of a signifier-the sound image (for instance of a tree) and signified — the concept (of the tree), the sign is considered to be psychological in nature. Meaning is understood to be arbitrary and relative and determined by the interaction between the signifier and the signified across the syntagmatic and the paradigmatic axes. Based on the relation between signifier and the signified, CS Peirce has identified three types of signs-the iconic (where the resembles the signified, as in the case of a geographical map), indexical (where the relation between the signifier and the signified is that of cause/effect as that of smoke and fire) and the symbolic (where the relation is arbitrary and established by social/cultural convention, as in the case of the red traffic light signifying “stop”).
The concept of signifier and the signified is a path-breaking one in literary theory. In realism, there was no distinction between the “sound image” and the ‘concept’, while in Structurafis the signifier does not have a one to one relation with a signified, though meaning is assumed. In poststructuralism, the signifier inevitably leads to another signifier in an infinite chain of signifiers, and the final signified, what Derrida calls the “transcendental signified” is never attained.