'Synonymy' definitions:

Definition of 'synonymy'

From: WordNet
noun
The semantic relation that holds between two words that can (in a given context) express the same meaning [syn: synonymy, synonymity, synonymousness]

Definition of 'Synonymy'

From: GCIDE
  • Synonymy \Syn*on"y*my\, n. [L. synonymia, Gr. ? a synonym: cf. F. synonymie.]
  • 1. The quality of being synonymous; sameness of meaning. [1913 Webster]
  • 2. A system of synonyms. [1913 Webster]
  • 3. (Rhet.) A figure by which synonymous words are used to amplify a discourse. [1913 Webster]

Synonyms of 'synonymy'

From: Moby Thesaurus