Without the use of any modifiers, an organ is wind instrument with a keyboard for the musical notes to be played and foot pedals. When the keys on the keyboard are pressed it produces wind through timbres, which are called stops. These are arranged in four different family groups: flutes, strings, reeds and principles.
The instrument called a barrel organ is one that in some of its incarnations, provides music in clocks. Typically a barrel organ is a small pipe organ with a pinned wooden barrel that is turned by a crank. This is to provide both air and to rotate the barrel and its pins across keys that get engaged. One type of barrel organ is a bird organ which is meant to be used with caged birds, intended to make the birds sing.
There are also electronic organs, this is pipeless keyboard organ with many of the features found on a pipe organ. An electronic organ is able to play chords, sustain tones and crescendo and decrescendo on sustained tones. Many electronic organs have a variety or timbres to choose from similar to pipe organs. Electronic organs also combine pickups or transducers to create sound.
Another type of organ is a fairground organ. Fairground organs are used on merry-go-rounds or carousels. The original type of organ that was used for this purpose was a barrel organ, however later organs more like a piano player was developed. A generic term for instruments that vibrate freely with a keyboard and a reed that vibrates freely is a “reed organ.” Some instruments considered reed organs are concertinas, accordions or “mouth organs” more commonly known as harmonicas. A stream organ, also known as a calliope, is an instrument that uses a pinned cylinder and steam whistles to produce sound.
Other uses of the word organ refer to parts of an organic body, such as the lungs, liver, kidney or heart or an organ can refer to a newspaper, paper, journal, periodical, magazine, newsletter, gazette, publication or mouthpiece.