In music and musical analysis, a subsidiary chord is an elaboration of a principal harmonic chord in a chord progression.

If the principal chord (X) is partially replaced by the subsidiary (Y), there are three possible positions - beginning, middle, and end - for the subsidiary:^[1]

X–Ya

Y–X

X–Y–X

For example, a subsidiary chord in a modulation.

A subsidiary chord may be a chord with related function and/or sharing pitches, for example in E major, C♯m (C♯-E-G♯) as a subsidiary for E (E-G♯-B), which share two of three pitches and are related as tonic parallel (vi) and tonic (I).

References

Triad	Major Minor Augmented Diminished Suspended
Seventh	Leading-tone Major Minor Dominant Dominant seventh flat five Diminished Half-diminished Diminished major Minor-major Augmented major Augmented minor Altered seventh Nondominant Harmonic seventh
Extended	Ninth Eleventh Thirteenth Upper structure Dominant 7♯9 Polychord Tone cluster
Added / omitted	Sixth Augmented sixth Lydian Seven six
Specific	Alpha Bridge Complexe sonore Dream Elektra Farben Grandmother Magic Mystic Northern lights Petrushka Psalms So What Tristan Viennese trichord
General	Mixed interval Secundal Tertian Quartal Synthetic chord Tetrad

By function

Diatonic	Tonic Supertonic Mediant Subdominant Dominant Submediant Leading-tone / Subtonic
Altered	Approach Borrowed Chromatic mediant Neapolitan Passing
Secondary	Secondary dominant Secondary leading-tone Secondary supertonic
Other	Common Contrast Primary triad Subsidiary Substitute

Techniques

Other

See also

References

Further reading