tuning fork
A two-pronged metal device that produces a pure tone when struck, used as a pitch reference.
In Depth
A tuning fork produces an almost pure sine wave — a single frequency with virtually no overtones — when struck against a hard surface. The most common tuning fork vibrates at 440 Hz, producing the standard concert A. Musicians place the base of the vibrating fork on a hard surface to amplify the sound. Invented in 1711 by John Shore, a trumpeter in Handel's orchestra, the tuning fork provided the first reliable, portable pitch reference. Before tuning forks, musicians tuned to whatever reference was available — church organs, other instruments, or simply convention. Electronic tuners have largely replaced tuning forks in practice, but many musicians still carry one as a backup.
The tuning fork was invented by John Shore in 1711 — a trumpeter who reportedly grew tired of tuning to out-of-tune church organs and decided to create a reliable portable reference.