The hurdy-gurdy is a string instrument that produces sound by means of a hand-cranked rosined wheel which rubs against the strings. The wheel functions much like a violin (or nyckelharpa) bow, and single notes played on the instrument sound similar to those of a violin. Melodies are played on a keyboard that presses tangents—small wedges, typically made of wood or metal—against one or more of the strings to change their pitch. Like most other acoustic stringed instruments, it has a sound board and hollow cavity to make the vibration of the strings audible.

https://en.wikipedia.org/wiki/Hurdy-gurdy