The melodica, also known as the pianica, blow-organ, key harmonica, or melodyhorn, is a free-reed instrument similar to the pump organ and harmonica. It has a musical keyboard on top, and is played by blowing air through a mouthpiece that fits into a hole in the side of the instrument. Pressing a key opens a hole, allowing air to flow through a reed. The keyboard is usually two or three octaves long. Melodicas are small, light, and portable. They are popular in music education, especially in Asia.
The modern form of the instrument was invented by Hohner in the 1950s, though similar instruments have been known in Italy since the 19th century.
The melodica was first used as a serious musical instrument in the 1960s by composers such as Steve Reich, in his piece titled Melodica (1966) and jazz musician Phil Moore, Jr., on his 1969 Atlantic Records album Right On. Brazilian multi-instrumentalist Hermeto Pascoal developed a technique consisting of singing while playing the melodica, resulting in a wide tonal and harmonic palette. It is associated with Jamaican dub and reggae musician Augustus Pablo who popularized it in the 1970s.