Harmonic is an oscillation having a frequency is a simple multiple of a fundamental sinusoidal oscillation. The fundamental frequency of a sinusoidal oscillation is usually called the first harmonic. The second harmonic has a frequency twice that of the fundamental, and so on.
Generalic, Eni. "Harmonic oscillation." Croatian-English Chemistry Dictionary & Glossary. 29 June 2022. KTF-Split. {Date of access}. <https://glossary.periodni.com>.
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