The bandoneon is a musical instrument that is strongly associated with tango music. It is a type of accordion that consists of two rectangular bellows with buttons on both sides. While commonly known as a bandoneon, there are other names and synonyms for this instrument depending on the region or language. In Argentina, it is also called "bandonion" or "bandurria". In Uruguay, it is known as "concertina". In French, it is "bandoneon" or "bandonion". In German, it is called "bandonion", which is the most widely used term for the instrument. Despite the variations in name, the bandoneon remains a highly valued musical instrument that is perfect for expressing the passion and soulfulness of tango music.