seventone

Seventone is a term sometimes used in music theory and pedagogy to denote the seven distinct pitch classes contained within one octave in Western tonal music. The concept emphasizes that an octave spans seven unique tones before the pitch classes repeat at the octave, forming a seven-note collection known as a heptatonic set.

In practice, seventone is closely associated with seven-note scales such as the diatonic major and natural minor scales, as well as other seven-note collections used in tonal, modal, and modern harmonic contexts. The idea of a seven-tone set allows analysts to discuss intervallic structure, mode derivation, and transpositional invariance without committing to a single scale arrangement.

The term is often used informally to describe the pitch-class content that a melody or harmony employs within a given key. This can aid discussions of scale construction, modulation, and voice leading by focusing on the seven tones that participate in a passage, rather than on a specific starting note or mode.

Because seven-note systems exist in various forms and are sometimes defined differently in different theoretical traditions, seventone can be somewhat ambiguous. It is not a universally standardized term and is more common in introductory or exploratory discussions than in formal treatises.

See also: diatonic scale, heptatonic scale, octave equivalence.