Merriam-Webster Collegiate Dictionary - harmony

 noun  (plural -nies)  Etymology: Middle English armony, from Anglo-French armonie, from Latin harmonia, from Greek, joint, ~, from harmos joint — more at arm  Date: 14th century  1. archaic tuneful sound ; melody  2.  a. the combination of simultaneous musical notes in a chord  b. the structure of music with respect to the composition and progression of chords  c. the science of the structure, relation, and progression of chords  3.  a. pleasing or congruent arrangement of parts a painting exhibiting ~ of color and line  b. correspondence, accord lives in ~ with her neighbors  c. internal calm ; tranquillity  4.  a. an interweaving of different accounts into a single narrative  b. a systematic arrangement of parallel literary passages (as of the Gospels) for the purpose of showing agreement or ~