musical scale containing five different tones. It is thought that the pentatonic scale represents an early stage of musical development, because it is found, in different forms, in most of the world's music. The most widely known form is anhemitonic (without semitones; e.g., c–d–f–g–a–c′), the hemitonic form (with semitones; e.g., c–e–f–g–b–c′) occurring less frequently.

Pentatonic scales may have been used in ancient times to tune the Greek kithara (lyre), and some early Gregorian chant incorporated pentatonic melodies. A variety of pentatonic scales occur in the music of American Indians, black Africa, and Asia (e.g., the Javanese five-tone slendro), as well as in many European folk melodies. In Western art music, 20th-century composers such as Claude Debussy have used pentatonicism for special effects.