What family does the harmonica belong to?

The harmonica belongs to the family of instruments known as "free reed aerophones." These instruments produce sound by the vibration of a metal reed without the need for a vibrating string or membrane. The harmonica falls under the sub-category of "mouth-blown free reed aerophones," where the musician blows air into the instrument to cause the reeds to vibrate and produce sound. Other instruments in the same family include the accordion and the concertina.