A machine head (also referred to as a tuning machine, tuner, or gear head) is a geared apparatus for tuning stringed musical instruments by adjusting string tension.
stringed instrument 1
noundomain: artefact
Princeton WordNet [ver.3.1]
English
Definition
a musical instrument in which taut strings provide the source of sound
A machine head (also referred to as a tuning machine, tuner, or gear head) is a geared apparatus for tuning stringed musical instruments by adjusting string tension.