synonymy (n.)

• agreement
• coincidence
• congruence
• correspondence
• dictionary
• equality
• equivalence
• gazetteer
• gloss
• glossary
• homogeneity
• identity
• indistinguishability
• lexicon
• oneness
• onomasticon
• sameness
• selfsameness
• synonymity
• synonymousness
• thesaurus
• unity
• vocabulary
• wordbook