string quartet

WordReference Random House Unabridged Dictionary of American English © 2025

string′ quartet′, 

1. Music and Dance a musical composition, usually in three or four movements, for four stringed instruments, typically two violins, viola, and cello.
2. Music and Dance a first violinist, second violinist, violist, and cellist forming a group for the performance of string quartets and similar music.
• 1870–75

Collins Concise English Dictionary © HarperCollins Publishers::

string quartet noun

1. an instrumental ensemble consisting of two violins, one viola, and one cello
2. a piece of music written for such a group, usually having the form and commonest features of a sonata