From AMS Glossary
- Any integral multiple of the lowest (or fundamental) frequency of a physical system.
For example, the motion of a taut, gently plucked violin string is the superposition of sinusoidal motions with frequencies ω0, ω1 = 2ω0, ω2, 3ω0, . . . where ω0 is the fundamental frequency and ω1, ω2, . . . are the harmonics (or overtones), resulting in a harmonious composite sound.
- A sine or cosine component of the Fourier series representation of an empirical or theoretical function.