Quartet
Quartet , noun
[Italian quartetto, dim. of quarto the fourth, a fourth part, from Latin quartus the fourth. See Quart.]
1.
(a) (Music) A composition in four parts, each performed by a single voice or instrument.
(b)
(Music) The set of four person who perform a piece of music in four parts.
2.
(Poet.) A stanza of four lines.
Also: Quartette