diatonisch

Diatonisch, or diatonic in English, refers to scales, melodies, and harmonies that stay within the diatonic collection—seven distinct pitch classes arranged within an octave. In Western music, the diatonic set underpins much of the common-practice repertoire. A diatonic scale contains five whole steps and two half steps, arranged in characteristic patterns that produce the major scale as well as its parallel natural minor scale and related modes. Melodies and chords described as diatonic typically use only the notes from the key’s diatonic scale, though some borrowed tones from parallel keys may appear in non-diatonic passages.

The diatonic concept extends beyond a single scale to include diatonic modes: Ionian, Dorian, Phrygian, Lydian, Mixolydian, Aeolian, and Locrian. Each mode uses the same seven tones but starts on a different degree, giving distinct melodic implications while preserving the diatonic pitch set.

Diatonic triads built from diatonic scale degrees form the basis of diatonic harmony. In the major-minor system, these range from major and minor triads to diminished triads, and functional progressions move among tonic, subdominant, and dominant regions. Non-diatonic chords or chromatic passing tones are used sparingly in many styles, but diatonic harmony remains the core of traditional Western tonal music.

Historically, the term diatonic distinguishes music that adheres to the diatonic set from music that uses chromatic or atonal elements. In theory from the medieval to the present, diatonic has described the tonal framework of scales, chords, and voice leading that prevailed in much of Western music up to the 19th century, and in many genres remains a practical reference point today.