A chordophone is a musical instrument that makes sound by way of a vibrating string or strings stretched between two points. It is one of the four main divisions of instruments in the original Hornbostel-Sachs scheme of musical instrument classification. What many would call string instruments are classified as chordophones. Violins, guitars, lyres, and harps are examples. However, the word also embraces instruments that many would hesitate to call string instruments, such as the musical bow and the piano (which, although sometimes called a string instrument, is also called a keyboard instrument and a percussion instrument).

Hornbostel and Sachs’ criterion for determining which sub-group an instrument falls into is that if the resonator can be removed without destroying the instrument, then it is classified as 31. The idea that the piano’s casing, which acts as a resonator, could be removed without destroying the instrument, may seem odd, but if the action and strings of the piano were taken out of its box, it could still be played. This is not true of the violin, because the string passes over a bridge located on the resonator box, so removing the resonator would mean the strings had no tension.

3 Instruments in which sound is produced by one or more vibrating strings [chordophones, string instruments].

32 Instruments in which the resonator and string bearer are physically united and can not be separated without destroying the instrument

321 Instruments in which the strings run in a plane parallel to the sound table [lutes].

321.3 Instruments in which the string bearer is a plain handle [handle lutes].

321.32 Instrument in which the handle is attached to, or carved from, the resonator, like a neck [necked lutes].

321.321 Instrument whose body is shaped like a bowl (necked bowl lutes)
These instruments may be classified with a suffix, based on how the strings are caused to vibrate.

4 Hammers or beaters
5 Bare hands and fingers
6 Plectrum
7 Bowing
8 Keyboard
9 Using a mechanical drive

71 Using a bow
72 Using a wheel
73 Using a ribbon