Synonymousness and Semantic relation

Synonymousness noun - The semantic relation that holds between two words that can (in a given context) express the same meaning.

Semantic relation and synonymousness are semantically related. In some cases you can use "Semantic relation" instead a noun "Synonymousness".

Semantic relation noun - A relation between meanings.

Synonymousness and semantic relation are semantically related. Sometimes you can replace term "Synonymousness" with "Semantic relation", this terms are similar.