There are many names for the barrel organ, such as hand organ, cylinder organ, box organ (though that can also mean a positive organ), street organ, grinder organ, and Low Countries organ. In French names include orgue à manivelle ("crank organ") and orgue de Barbarie ("Barbary organ"); German names include Drehorgel ("crank organ"), Leierkasten ("brace box"), and Walzenorgel ("cylinder organ"); Hungarian names include verkli (from Austrian-German Werkl), sípláda ("whistle chest") and kintorna (from Bayern-Austrian "Kinterne"); Italian names include organetto a manovella ("crank organ") and organo tedesco ("German organ"); the Polish name is katarynka. However, several of these names include types of mechanical organs for which the music is encoded as book music or by holes on a punched paper tape instead of by pins on a barrel. While many of these terms refer to the physical operation of the crank, some refer to an exotic origin. The French name orgue de Barbarie, suggesting barbarians, has been explained as a corruption of, variously, the terms bara ("bread") and gwen ("wine") in the Breton language, the surname of an early barrel-organ manufacturer from Modena, Giovanni Barberi, or that of the English inventor John Burberry.
The term hurdy-gurdy is sometimes mistakenly applied to a small, portable barrel organ that was frequently played by organ grinders and buskers (street musicians), but the two terms should not be confused. Although the hurdy-gurdy is also powered by a crank and often used by street performers, it produces sound with a rosin-covered wheel rotated against tuned strings. Another key difference is that the hurdy-gurdy player is free to play any tune he or she desires, while the barrel organist is generally confined to pre-programmed tunes.
The pieces of music (or tunes) are encoded onto the barrel using metal pins and staples. Pins are used for short notes, and staples of varying lengths for longer notes. Each barrel usually carried several different tunes. Pinning such barrels was something of an art form, and the quality of the music produced by a barrel organ is largely a function of the quality of its pinning.
The organ barrels must be sturdy to maintain precise alignment over time, since they play the same programming role as music rolls and have to endure significant mechanical strain. Damage to the barrel, such as warpage, would have a direct (and usually detrimental) effect on the music produced.