When the word “organ” is used without any modifiers, it usually refers to a wind instrument with a keyboard and foot pedals. When you play the instrument, it activates the pipework, which produces sounds in a wide range of timbres, known as stops, that are divided into four categories: flutes, strings, reeds, and principals. This is the instrument that the term “church organ” refers to, as well as the version featured in The Phantom of the Opera.
The barrel organ is a mechanical instrument that provides music for clocks in some of its forms. It’s usually a small pipe organ with a crank that turns a pinned wooden barrel. This both provides air and rotates the barrel and its pins across engaged keys, which play a tune depending on the pin placement. The bird organ is a type of barrel organ that is used to encourage caged birds to sing.
The electronic organ is a pipeless keyboard organ with many of the same features as a pipe organ. They can play chords, sustain tones, and crescendo and decrescendo sustained tones. Many, like pipe organs, offer a variety of timbres. An electric organ is an electronic instrument that uses pickups or transducers to combine acoustic and electronic sounds.
On carousels and merry-go-rounds, a fairground organ is a mechanical instrument. While barrel organs were the first of this type, a mechanism more akin to a player piano was developed. The term “reed organ” refers to any instrument with a keyboard and a freely vibrating reed, such as accordions, concertinas, and harmonicas, which are also known as mouth organs. A pinned cylinder and steam whistles produce sound in a calliope or steam organ. It was popular on river showboats and was featured in the 1951 film Showboat.
In other contexts, the word organ can refer to both major, self-contained body components like the heart, liver, skin, kidneys, and brain, as well as a newspaper or periodical that serves as an organization’s voice.