Model railroad type example Sn3.5 is as follows, S (scale) being the prefix to n (narrow gauge) followed by 3.5 (prototype track gauge in feet), 3 and 1/2 feet, or 42 inches, which in Sn3.5 equates to actual modeling track width of .649 - .672 thousandths, 16.5 - 17.1 mm.
Definition of harmonic. 1  1a : overtone; especially : one whose vibration frequency is an integral multiple of that of the fundamentalb : a flutelike tone produced on a stringed instrument by touching a vibrating string at a nodal point.
A harmonic frequency is a multiple of a fundamental frequency, also called harmonic. Especially when it comes to counting, do not say: overtones are harmonics. Musicians prefer the term overtones and physicists prefer the term harmonics. Sound engineers are somewhat uncertain between these two terms. harmonic frequency is a multiple of a fundamental frequency, also called harmonic. Especially when it comes to counting, do not say: overtones are harmonics. Musicians prefer the term overtones and physicists prefer the term harmonics. Sound engineers are somewhat uncertain between these two terms.