sign. A sign has three essential characteristics: it must have a physical form, it must refer to something other than itself, and it must be used and recognized by people as a sign. Barthes gives the example of a rose: a rose is normally just a flower, but if a young man presents it to his girl friend it becomes a sign, for it refers to his romantic passion, and she recognizes that it does.

Signs, and the ways they are organized into codes or languages, are the basis of any study of communication. They can have a variety of forms, such as words, gestures, photographs or architectural features. Semiotics, which is the study of signs, codes and culture, is concerned to establish the essential featurcs of signs, and the ways they work in social life.

Saussure divides a sign into its two constituent elements—the signifier (its physical form as perceived by our senses), and the signified (the mental concept of what it refers to). Peirce thinks that there are three types of signs - icons, indexes and symbols. Both these early authorities have had a considerable influence over later work in this area.

Saussure stresses that a sign can properly be understood only in relation to other signs in the same code or system: its meaning is determined partly by other signs which it is not. [see: difference] The significance of a bowler hat is clear only when we say it is not a topper, and not a trilby. The sign BOY is understood as not-MAN or not-GIRL, and MAN as not-ANIMAL, or not-GOD. As a linguist, Saussure is primarily interested in the relation of signs to each other within a code, and in the relationship of signifer to signified within a sign. He is less interested in the relationship of a sign to its referential reality (which he calls signification).

Peirce, on the other hand, gives this relationship at least as much emphasis as others. He, like his followers Ogden and Richards, takes the viewpoint of a philosopher, and believes that a sign can be studied only in relationship to two other elements which we can simplify into the terms mind and referential reality.His terms for them are, respectively, the interpretant and the object; Ogden and Richards's terms are the reference and the referent. [from: O'Sullivan 1994]