A part-song is a song written for several voice parts at once — typically soprano, alto, tenor, and bass — so different singers hold different lines that fit together. It is usually sung without a piano or other instruments; the voices are the whole piece. The ‘part’ is a musical line, not ‘a piece of a song’ and not ‘part-time’. Part-songs are often short, tuneful, and meant for a choir or a small group rather than one solo star. The term is especially at home in British choral music. A hymn with organ is not automatically a part-song; a pop song with a singer and a band is not one either. People sometimes use it loosely for any unaccompanied choir piece, though musicians may be more particular.