harmon- +

(Greek > Latin: a fitting together, joining, proportion, concord, agreement, musical harmony)

anharmonic
1. Not harmonic.
2. A reference to an oscillating system that is not undergoing simple harmonic motion.
contraharmonical, contraharmonically
Opposed to or the opposite of harmonical.
disharmonic
Not harmonic; without harmony; anharmonic.
disharmonious
Lacking in harmony; discordant.
disharmonize, disharmonise (British)
1. To put out of harmony.
2. To destroy the harmony of.
3. To make unharmonious or discordant.
4. To be out of harmony; not to harmonize.
disharmony
1. Lack of harmony; discord.
2. Something which is not in accord; a conflict.
3. A combination of sounds considered dissonant or unpleasant.
enharmonic, enharmonically
Relating to, or involving tones that are identical in pitch but are written differently according to the key in which they occur; such as, C sharp and D flat.
euharmonic
1. Producing mathematically perfect harmony or concord; sweetly or perfectly harmonious.
2. Producing harmony or concordant sounds; as the euharmonic organ.
Harmonia
In Greek mythology, Harmonia is the immortal goddess of harmony and concord.

Her Roman counterpart is Concordia, and her Greek opposite is Eris, whose Roman counterpart is Discordia.

harmonic
1. A reference to harmony, as distinguished from melody and rhythm.
2. Marked by harmony; in harmony; concordant; consonant.
3. In physics, a reference to, or noting a series of oscillations in which each oscillation has a frequency that is an integral multiple of the same basic frequency.
4. Involving or characterized by harmony.
5. A description of electrical voltages or currents with frequencies that are integral multiples of the fundamental frequency; that is, if 60 Hz is the fundamental frequency, then 120 Hz is the second harmonic and 180 Hz is the third harmonic.
harmonica
1. A musical wind instrument consisting of a small rectangular case containing a set of metal reeds connected to a row of holes, over which the player places his/her mouth and exhales and inhales to produce the tones. Also known as a "mouth organ".
2. Any of various percussion instruments that use graduated bars of metal or other hard material as sound producers.
3. An instrument consisting of tuned strips of metal or glass fixed to a frame and struck with a hammer.

The term armonica was coined in 1762 by the American physicist and statesman, Benjamin Franklin, for a musical instrument consisting of a set of water-filled glasses tuned to different notes and played with the fingers.

Harmonica was first applied to the "mouth-organ" in 1873; which is an alteration of the earlier armonica or glass harmonica.

harmonical
1. Involving or characterized by harmony.
2. Concordant; musical; consonant; such as, harmonic sounds.
harmonically
1. Of or relating to harmony.
2. Pleasing to the ear.
3. Characterized by harmony.
4. Of or relating to harmonics.
harmonicon
1. A small, flat, wind instrument of music, in which the notes are produced by the vibration of free metallic reeds.
2. Any of various percussion instruments that use graduated bars of metal or other hard material as sounding elements.
harmonics
1. The science of musical sounds.
2. The partials or overtones of a fundamental tone.
3. Integral multiples of the fundamental frequency.

The first harmonic is the fundamental, and the second is twice the frequency of the fundamental, etc. Also called overtones, these are vibrations at frequencies that are multiples of the fundamentals. Harmonics extend without limit beyond the audible range.