QUARTER NOTE - A note played for one quarter of the length of a whole note. For example, in 4/4 meter the quarter note receives one beat of sound.
QUARTER REST - A rest played for one quarter of the length of a whole rest. For example, in 4/4 meter the quarter rest receives one beat of silence.
QUARTET - A musical ensemble made up of four instruments or singers, each playing a separate part.
QUINTET - A musical ensemble made up of five instruments or singers, each playing a separate part.