Diatonic

A diatonic scale is a seven-note scale built from a fixed pattern of whole and half steps — the major and natural minor scales are its two most common examples. The term contrasts with "chromatic" (all twelve half steps with no distinction) and "pentatonic" (only five notes, no half steps at all).

Why diatonic is the norm, not the exception

Nearly all Western melodies and chord progressions rely on a diatonic scale, precisely because the uneven spread of whole and half steps creates degrees that sound more stable (the tonic) and others more tense (the leading tone, right before the tonic) — that hierarchy is what gives a cadence its meaning, while a chromatic scale ranks nothing at all.

The C major scale in open position is the catalog's most direct example of a diatonic scale.

Diatonic, chromatic, pentatonic: three ways of counting notes

These three terms answer each other: chromatic uses all twelve half steps with no hierarchy at all, pentatonic keeps only five and drops the half steps entirely, diatonic keeps seven with exactly two half steps placed at specific spots. It's that precise placement, not the note count by itself, that creates the hierarchy of degrees (a stable tonic, a tense leading tone) that every cadence relies on.

Practical tips and common mistakes

• Don't confuse "diatonic" with "major scale": the natural minor is just as diatonic. The word describes a structure (seven notes, two half steps), not a particular colour.
• Spot the two half steps of a diatonic scale (between the 3rd and 4th degree, and between the 7th and 1st in major): they're what explains why some chords "pull" toward the tonic more than others.
• A progression that stays diatonic (every chord drawn from the same seven-note scale) sounds predictable in the good sense of the word; a chord borrowed from another scale creates a deliberate break, often used to surprise the ear.
• The term applies to chords just as much as scales: a key's seven diatonic chords correspond to its seven degrees, I through VII.