The hurdy-gurdy is played by rubbing a bow-like wheel across strings while keys change the stopped notes.
The player turns a hand crank, rotating a rosined wooden wheel. The wheel acts as a continuous bow, producing sound from melody strings and often from drone strings. A keyboard presses tangents against selected strings to change their effective vibrating length and therefore their pitch.
The instrument appeared in Europe during the medieval period and was known by several names, including vielle à roue in French. Its sustained drone sound connects it with bagpipes and other traditional instruments, although its sound-producing mechanism is entirely different.
Despite its name, the hurdy-gurdy is not a barrel organ. A barrel organ uses a rotating pinned cylinder to control pipes, whereas the hurdy-gurdy uses a wheel to excite strings. Historical and modern versions vary considerably in size, stringing and keyboard arrangement.