Chord Tone (CT)
In the
Chord
A note that belongs to the currently playing chord — the root, major 3rd, perfect 5th, or 7th. The chord supports and "catches" this note. It sounds harmonically expected.
vs
Non-Chord Tone (NCT)
Outside
the Chord
A note that does NOT belong to the chord. The chord doesn't catch it. Depending on key stability, this creates floating color, grounded tension, or dissonant edge.
✓ Chord Tones — C Major (DO · MI · SO)
These notes are harmonically supported. Stable key degrees + chord tones = Zone 1 (Sweet/Grounded). Melody and harmony fully agree. The ear hears arrival, warmth, and confidence.
✗ Non-Chord Tones — Outside C Major
These notes float above C major. RE, FA, TI = Zone 4 (Bitter/Edgy — unstable + non-chord). LA = Zone 3 (Floating/Modern — stable enough to add color without harsh friction). Change the chord to claim these notes.
Zone Result — All 7 Notes Over C Major
Solid outline = chord tone
Dashed outline = non-chord tone
The Core Principle
The chord under the melody determines which notes feel grounded and which create tension.
Change the chord to C → F, and the same FA that was Zone 4 (Bitter) over C becomes Zone 2 (Tense/Supported) over F — because FA is now the root. The pitch doesn't change. The context transforms everything.