Recitative is used in vocal works, particularly opera and oratorio, usually for a solo voice, in relatively free rhythm. In this respect recitative is distinct from the formal aria. Recitative might be accompanied by basso continuo, harpsichord or other chordal instruments and a bass instrument (recitativo secco or dry recitative), or accompanied by a larger number of instruments (recitativo accompagnato, accompanied recitative). Recitative is often used for narrative or for the forwarding of the plot in opera.