Synonymy

Abstract

Those who write about synonymy (in earlier works, often synonymity) tend to claim either that it is the most common lexical relation or that it does not exist. These positions depend entirely on how one defines the term: either as “similarity of meaning” or “identity of meaning,” respectively. The usual test for synonymy is substitution: if one expression can be replaced by another in a sentence without change to the meaning of the sentence, then the two expressions are said to be synonyms. Absolute synonyms are substitutable in all possible contexts in all possible (semantic, grammatical, sociolinguistic) ways. Synonymy is a relation between individual senses of words, so that a single word typically has different sets of synonyms for each of its senses. For example, coat has different synonyms for its senses ‘outer garment’ (e.g., jacket) and ‘covering layer’(e.g., layer). Other synonym terms distinguish types of semantic overlap between words: identity of sense (perfect, or exact, synonymy: myopia~near-sightedness) versus overlap (near-synonymy: advice~suggestion); similar but non-identical referents (plesionymy: fog~mist); and differences in level of specificity (hyponymy: shoe~footwear). Finally, synonyms may be categorized by their non-referential meaning differences, such as register (tired~knackered), dialect (highway~motorway), or language (dog~chien). Like its converse, polysemy, lexical synonymy undermines linguistic economy—having more than one form to express a single meaning is inefficient. It would be economical for languages to avoid absolute synonymy, and indeed they seem to. But languages tolerate a large amount of semantic overlap and replication of meanings in different registers. In modern times, synonymy was initially a problem that lexicographers tackled. Dictionaries of synonyms were published in English from the 18th century, and Roget’s invention of the modern thesaurus in 1852 brought more attention to the problem of how words relate to one another. Philosophy and linguistic theory followed. European structuralist linguistics of the 20th century treated individual word meanings as emerging from the relations between words. Meanwhile, more formal-semantic approaches saw synonymy as a descriptive and diagnostic tool for determining the representation of meaning. Attention to synonymy has returned in the present century within usage-based theories of meaning. Today’s synonym investigations are supported by computational methods for modelling synonymy and corpus methods for investigating it.