Diatonic button accordion

Melodeon
Classification Free-reed aerophone
Hornbostel–Sachs classification412.132
(sets of free reeds)
Musicians
List of accordionists
More articles or information
Accordion, Chromatic button accordion, Bayan, Diatonic button accordion, Piano accordion, Stradella bass system, Free-bass system, Accordion reed ranks & switches

A melodeon or diatonic button accordion is a member of the free-reed aerophone family of musical instruments. It is a type of button accordion on which the melody-side keyboard contains one or more rows of buttons, with each row producing the notes of a single diatonic scale. The buttons on the bass-side keyboard are most commonly arranged in pairs, with one button of a pair sounding the fundamental of a chord and the other the corresponding major triad (or, sometimes, a minor triad).

Diatonic button accordions are popular in many countries, and used mainly for playing popular music and traditional folk music, and modern offshoots of these genres.