High Quality Content by WIKIPEDIA articles! The piano is a musical instrument played by means of a keyboard. It is one of the most popular instruments in the world. Widely used in classical and jazz music for solo performances, ensemble use, chamber music and accompaniment, the piano is also very popular as an aid to composing and rehearsal. Although not portable and often expensive, the piano`s versatility and ubiquity have made it one of the world`s most familiar musical instruments.