pl. (Mus.) Secondary and less distinct tones which accompany any principal, and apparently simple, tone, as the octave, the twelfth, the fifteenth, and the seventeenth. The name is also applied to the artificial tones produced by a string or column of air, when the impulse given to it suffices only to make a part of the string or column vibrate; overtones.
... undulations blended together, so the tidal wave consists of a number of distinct undulations superposed. Of these the ordinary lunar tide and the ordinary solar tide are the two principal; but there are also minor undulations, harmonics, so to speak, some originating from the moon, some originating from the sun, and some from ... — Time and Tide - A Romance of the Moon • Robert S. (Robert Stawell) Ball