Chord organ
Chord organ is a kind of home organ that has a single short keyboard and a set of chord buttons, enabling the musician to play a melody or lead with one hand and accompanying chords with the other, like the accordion with a set of chord buttons which was originated from a patent by Cyrill Demian in 1829, etc. Initially, the chord organ was invented as a kind of electronic home organ by Laurens Hammond in 1950.