Piano four hands
Piano four hands (French: À quatre mains, German: Zu vier Händen, Vierhändig, Italian: a quattro mani) is a type of piano duet in which the two players play a piece arranged for four hands on the same piano simultaneously. A duet with the two players playing separate pianos is generally referred to simply as a piano duet or piano duo.
Music written for piano four hands is usually printed so that left-hand pages contain only the part for the pianist sitting on the left, while right-hand pages contain only the part for the pianist sitting on the right. The upper part (right) is called primo while the lower part (left) is called secondo.