quadrivium Subdivision of the seven liberal arts; includes the mathematical subjects of music, arithmetic, geometry, and astronomy.

quadruple meter Basic metrical pattern of four beats to a measure. Also common time.

quadruple stop Playing four notes simultaneously on a string instrument.

quadruplum Fourth voice of a polyphonic work.

quartal harmony Harmony based on the interval of the fourth as opposed to a third; used in twentieth-century music.

quotation music Music that parodies another work or works, presenting them in a new style or guise.