Tetrachord

In musical theory, a tetrachord is a series of four diatonic tones encompassing the interval of a perfect fourth.

Two similar tetrachords, a tone apart, form the diatonic major scale.

External links

• Greek Esoteric Music Theory: The Elemental Tetrachord (http://www.cs.utk.edu/~mclennan/BA/GEM/GEM-ET.html)