
[American Spanish bandoneón, from German Bandonion, Bandoneon : Heinrich Band (1821-1860), German inventor + (Akkord)ion, accordion; see accordion.]
bandoneonist ban·do'ne·on·ist (-ə-nĭst) n.
A square-build button accordion or concertina, invented in the 1940s by Heinrich Band of Krefeld. It has been used in dance orchestras in South America and West Africa, and by some USA avant-garde composers.