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.