Definition of: harmonic

(här·mon′ik) adjective
1. Producing, characterized by, or pertaining to harmony; consonant; harmonious.
2. Music a Pertaining to harmony, as distinguished from melody or rhythm. b Pertaining to a tone whose rate of vibration is an exact multiple of a given primary tone.
3. Math. Derived from or originally suggested by the numerical relations between the vibrations of the musical harmonics or overtones of the same fundamental tone: harmonic functions.
—noun
1. An attendant or secondary tone, produced by the vibration in aliquot parts of the same body or string which gives, by its complete simultaneous vibration, the primary or fundamental tone; overtone.
2. Music A note on a stringed instrument produced by stopping a string at a specific point.
3. Physics Any component of a periodic quantity which is an integral multiple of the fundamental frequency. Also har·mon′i·cal. [<L harmonicus <Gk. harmonikos <harmonia harmony]
—har·mon′i·cal·ly adverb