The piano is a musical instrument played using a keyboard, which is a row of small levers that the performer presses down or strikes with the fingers and thumbs of both hands. Although the piano is not portable and is often expensive, its versatility, wide range, ability to play chords, ability to play louder or softer, the large number of musicians trained in playing it and its ubiquity in performance venues and rehearsal spaces have made it one of the Western world's most familiar musical instruments. Someone who plays the piano is called a pianist.