quartet

1. A group of four people or things, particularly
2. A group of four musicians who perform classical music together. · The string quartet played some chamber music.
3. A musical composition in four parts, each performed by a single voice or instrument. · He composed a string quartet.
4. A group of four singers that sing together in four-part harmony. · The barbershop quartet performed the composition a cappella.

الجمع quartets