Pianos and organs belong to the keyboard family of musical instrument which also includes pipe organ, hurdy gurdy, clavichord, harpsichord, accordion and many more. The organ is the oldest keyboard instrument. Pianos appeared in the 18th century and quickly became popular, because they enable the player to vary the volume of sound by varying the force with which the keys are struck. Another name for piano is "piano-forte", which means "soft-loud" in Italian.