An electronic organ is an electronic keyboard instrument which was influenced from harmonium, or pipe organ and theatre organ. In early days, it was designed to imitate the sound of a pipe organ, theatre organ, band sounds, or orchestral sounds. Today, it has developed into three or more forms of the instrument; the Hammond organ-style instrument used in popular music genre; the digital church organ that imitates a pipe organ for classical music and use in churches; and various type of organs from other manufacturers includes combo organ, home organ, and software organs, etc.