According to the Grove Dictionary of Music and Musicians, there are two kinds of piano duet: "those for two players at one instrument, and those in which each of the two pianists has an instrument to him- or herself." In American usage the former is often referred to as "piano four hands". Grove notes that the one-piano duet has the larger repertory, but has come to be regarded as a modest, domestic form of music-making by comparison with "the more glamorous two-piano duet". The latter is more often referred to as a piano duo.