Chorus (héchàng；; ; Chorus refers to the artistic category of collective singing of multi-voice vocal works, which is mostly performed with or without accompaniment. String quartet, as its name implies, is "a form of chamber music composed of four stringed instruments". It consists of two violins, a viola and a cello, and is the most important and popular type of chamber music.

Quartet is a musical form dominated by string quartet. Quartet: In the field of quartet, string quartet is the most important and largest form.