Synonymous relation is a kind of special and important paradigmatic relation in vocabulary.
From the theory of semantic, we know it includes syntagmatic relations and paradigmatic relations.
Saussure's research on the syntagmatic relationship and paradigmatic relationship of language signs gives guidelines to Roman Jakobson's study of "poetic function"of the literary language.
Language is a system of symbols based on relations, among which syntagmatic and paradigmatic relations are the most universal and important ones.
