ac ‧ cor ‧ di ‧ on /əˈkɔːdiən $ əˈkɔːr-/ BrE AmE ( also piano accordion British English ) noun [countable]
[ Date: 1800-1900 ; Language: German ; Origin: akkordion , from akkord 'chord' , from French accord ]
a musical instrument like a large box that you hold in both hands. You play it by pressing the sides together and pulling them out again, while you push buttons and ↑ key s .
—accordionist noun [countable]