Synthetic chord

A synthetic chord is a made-up or non-traditional chord which cannot be analyzed in terms of traditional music theory or harmonic analysis. If a composer uses a synthetic scale as the basis for a passage of music and makes up chords out of some of its notes, in much the same way that a tonal composer may use a major or minor scale's notes to build harmonies, then the resulting chords may be referred to as synthetic chords.

The term "Synthetic chord" is also occasionally used to refer to the chord devised by Scriabin, and far better known as his Mystic chord or Prometheus chord. It is an example of a synthetic chord - perhaps the best-known one - but it is only one of many possible examples, and it is not strictly correct to refer to this as "the" synthetic chord, since it can in fact be described as an altered dominant chord.

An example of a synthetic chord would be the repeated chord in the first act of Puccini's "Turandot" at the beginning of the text passage "Non indugiare, se chiami appare...".