ARC Music | Tetrachord

The perfect fourth and the set of four diatonic, chromatic, or enharmonic notes encased therein.

Term applied to the intervals of a unison, octave, fourth, and fifth when they are exactly in tune and not augmented nor diminished.

An interval of four diatonic scale tones, counting the first and last tone. For example, the interval from C to F is a fourth.

1. Any music or chord that contains notes not belonging to the diatonic scale.
2. Music which proceeds in half steps.

A notational symbol used to represent the duration of a sound, and when placed on a music staff, also indicate the pitch of the sound.