#overtone

• Aliquot — A specialized term used in acoustics and music to describe an aliquot part of a vibrating string or air column that produces an upper harmonic sound (aliquot tone). In organology and instrument making, it defines the system of aliquot (resonating) strings added to certain pianos (Blüthner system) or violins (like the viola d'amore), which are not struck directly but vibrate freely by sympathy, enriching the musical timbre.
• Harmonic — Based on harmony, balanced proportion, and structural concordance of elements within an assembly. In physics and acoustics, it describes a periodic oscillatory phenomenon (harmonic motion) or a sinusoidal component (harmonic frequency) of a complex sound, whose frequency is an integral multiple of the fundamental frequency. In mathematics, it refers to means or progressions established according to specific proportions, and in music, it designates the consonant relationship between simultaneously emitted sounds.
• Harmonica — A wind musical instrument consisting of a series of flexible metal reeds mounted inside channels of a wooden or plastic casing, activated by blowing or suction; also, in acoustics, a sinusoidal component of a complex sound whose frequency is an integral multiple of the fundamental frequency, thus defining the specific timbre of an instrument.
• Harmonic overtone — A secondary sound, an echo, or a harmonic resonance that accompanies a primary noise; an acoustic or semantic vibration that perfectly consounds with a reference element. In a structural sense, it defines the sonic component resulting from the process of resonance.