Quartet \Quar*tet"\, Quartette \Quar*tette"\, n. [It. quartetto, dim. of quarto the fourth, a fourth part, fr. L. quartus the fourth. See Quart.]

1. (Mus.)
   (a) A composition in four parts, each performed by a single voice or instrument.
   (b) The set of four person who perform a piece of music in four parts.

2. (Poet.) A stanza of four lines.

Source: Webster's Revised Unabridged Dictionary (1913)