A concerto is a musical composition typically featuring a solo instrument accompanied by an orchestra. The most common instruments used in concertos are the OBOE (4 letters), PIANO (5 letters), VIOLA (5 letters), and CADENZA (7 letters). The OBOE is a woodwind instrument with a double reed mouthpiece, the PIANO is a keyboard instrument with strings that are struck by hammers, the VIOLA is a bowed string instrument similar to the violin but larger in size, and the CADENZA is a solo passage usually near the end of a concerto.