Definition of "synonymy"

(semantics) The quality of being synonymous; sameness of meaning.  examples

A list or collection of synonyms, often compared and contrasted.  examples

The study of synonyms.  examples

A system of synonyms.  examples

(botany) The collective synonyms (all the names referring to a particular taxon, except the correct name)  examples

(botany) The state of not being a correct name, of being a synonym  examples

(zoology) The collective synonyms (all the names referring to the same taxon, including the correct name)