Harmony  n. (pl. -ies) 1 combination of simultaneously sounded musical notes to produce chords and chord progressions, esp. As creating a pleasing effect. 2 a apt or aesthetic arrangement of parts. B pleasing effect of this. 3 agreement, concord.  in harmony 1 in agreement. 2 (of singing etc.) Producing chords; not discordant. [greek harmonia joining]