harmony has 4 distinct synonyms spread across 4 of its 5 senses. Each sense below keeps its own list, because a synonym belongs to a meaning and not to a word: swapping one sense's substitute into another sense's sentence is how a thesaurus makes writing worse. Its one recorded opposite is dissonance.
Counts are distinct word forms across every sense. A synonym that appears under three senses is counted once here and shown three times below, under each sense it belongs to.
compatibility in opinion and action
the structure of music with respect to the composition and progression of chords
Synonyms, antonyms and the broader and narrower relations for harmony come from Princeton University’s WordNet. Full sources and licences.
an agreeable sound property