continuo

or basso continuo

In Baroque music, a special subgroup of an instrumental ensemble. It consists of two instruments reading the same part: a bass instrument, such as a cello or bassoon, and a chordal instrument, most often a harpsichord but sometimes an organ or lute. Its appearance in the early 17th century reflected the radically new musical texture of accompanied melody that was especially typical of the new vocal genre of opera. The continuo (which has a counterpart in the bass and rhythm guitar of a rock band) came to be employed in virtually all ensemble music of the Baroque era.

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