Clarinet (klăr-ĭ′-nĕt) or Clarionet, a wind-instrument, usually of wood, in which the sound is made by a single thin reed. It was probably invented by Joseph Denner, of Nuremberg, in 1690; but it has since then been much changed and improved, so that it now is one of the best of wind-instruments. The tube is round, and enlarged at the end in the form of a bell. It has holes to be covered by the fingers and left thumb, and keys, usually 13, to give the extra tones. The mouthpiece is flattened on one side, along which the reed is laid, leaving a slight opening so that when blown the reed vibrates against the mouthpiece and thus causes the sound. The clarinet has a much greater compass than the flute. It is used in orchestras and is the leading instrument in military bands.