adj. & n.
adj. 1 of or characterized by harmony; harmonious. 2 Mus. a of or relating to harmony. b (of a tone) produced by vibration of a string etc. in an exact fraction of its length. 3 Math. of or relating to quantities whose reciprocals are in arithmetical progression (harmonic progression).
n. 1 Mus. an overtone accompanying at a fixed interval (and forming a note with) a fundamental. 2 Physics a component frequency of wave motion. harmonic motion (in full simple harmonic motion) oscillatory motion under a retarding force proportional to the amount of displacement from an equilibrium position. harmonic progression (or series) Math. a series of quantities whose reciprocals are in arithmetical progression. harmonically adv.
[ L harmonicus f. Gk harmonikos (as HARMONY) ]