melodeon

Etymology 1
From, with change of ending.

Noun

 * 1)  A type of reed organ with a single keyboard.
 * 2)  An accordion where the melody-side keyboard is limited to the notes of diatonic scales in a small number of keys.
 * 1)  An accordion where the melody-side keyboard is limited to the notes of diatonic scales in a small number of keys.

Noun

 * 1)  A music hall.