What is the meaning of Synonymy?

The quality of being synonymous; sameness of meaning.

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

The use of synonyms to clarify or explain one's meaning.

The study of synonyms.

A system of synonyms.

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

The state of not being a correct name, of being a synonym

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

Source: wiktionary.org