A hurdy gurdy (or hurdy-gurdy, also known as a wheel fiddle) is a stringed musical instrument in which the strings are sounded by means of a rosined wheel which the strings of the instrument pass over. This wheel, turned with a crank, functions much like a violin bow. Melodies are played on a keyboard that presses tangents (small wedges, usually made of wood) against one or more of these strings to change their vibrating length, and therefore pitch.
Most hurdy gurdies have multiple "drone strings" which provide a constant pitch accompaniment to the melody, resulting in a sound similar to that of bagpipes. For this reason, the hurdy gurdy is often used interchangeably with or along with bagpipes, particularly in French and contemporary Hungarian folk music.
Many folk music festivals in Europe feature music groups with hurdy gurdy players, but the most famous annual festival is at Saint-Chartier, in the Indre département, in central France, during the week nearest July 14 (Bastille Day).