#1 harmonic a. of or relating to harmony as distinct from melody and rhythm; "subtleties of harmonic change and tonality"- Ralph Hill. wn #2 harmonic n. a tone that is a component of a complex sound. wn #3 harmonic n. any of a series of musical tones whose frequencies are integral multiples of the frequency of a fundamental. wn #4 harmonic a. of or relating to harmonics. wn #5 harmonic a. of or relating to the branch of acoustics that studies the composition of musical sounds; "the sound of the resonating cavity cannot be the only determinant of the harmonic response". wn