The chord organ is a kind of home organ with a 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. It was invented by Laurens Hammond in 1950 as an electronic home organ based on vacuum-tube circuits similar to the Novachord and Solovox.
^"Laurens Hammond". Encyclopædia Britannica Online. 2009. His later inventions included ... the chord organ (1950), on which chords are produced simply by touching a panel button. (Note: In 1950, Hammond introduced S-6 chord organ)
^WurlitzerModel 4100 BP (1959–1963) has chord unit on lower left. See image for details.