noun
bandoneon
A type of concertina especially associated with Argentine tango music.
バンドネオンの音色はタンゴに欠かせない。
The sound of the bandoneon is essential to tango.
コンサーティーナ is a similar free-reed instrument, but バンドネオン is larger and has a different button arrangement and timbre.
From Spanish 'bandoneón', named after the German instrument maker Heinrich Band.