This article gives a survey of the possible interpretations of word synonymy, which is relevant within the framework of a theory of denotation , but not in a theory of meaning (connotations, registers). Word synonymy dealing with coded items and sentence synonymy dealing with free items are of no interest to linguists. What allows meaning to be assessed is the coded → uncoded relation, in which the analytical uncoded item is the interpretant (Ch. S. Peirce). As the interpretant is made of words, the word is therefore the semantic unit (and not the metalinguistic seme).