Subsidiary chord

Not to be confused with Secondary chords.
Tonic and tonic parallel in C major: CM and Am chords Playⓘ.

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
Modulation with subsidiary chord (in blue).[2] Playⓘ

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).

  1. ^ van der Merwe, Peter (2005). Roots of the Classical: The Popular Origins of Western Music, p.501. ISBN 0-19-816647-8.
  2. ^ Becker, Julius (1845). A concise treatise on harmony, p.17. Ewer & Co.