hexatonic scale, musical scale containing six different tones within an octave. Using the syllables ut, re, me, fa, sol, and la to refer to the pitches, the 11th-century Italian theorist Guido d’Arezzo identified three hexatonic scales—which he called hexachords—built of whole- and half-step intervals. These scales provided a theoretical and practical foundation for the training of singers during the late Middle Ages and the Renaissance.
Beyond the realm of European music, hexatonic scales may contain unusually wide intervals, in which case they often are described as “gapped scales.” Hexatonic scales are especially common in the music of Native American peoples, notably those of the Northeast, Southeast, Southwest, and Northwest Coast regions.