Section 32.4 Polychords
A polychord typically consists of two triads sounding simultaneously. A polychord could also consist of two seventh chords, or a seventh chord and triad. Additionally, a polychord could conceivably consist of more than two triads or seventh chords, since the prefix “poly” means “many.”
Perhaps the most famous polychord is the “Rite of Spring chord,” an E♭\(\left.\text{}^{7}\right.\) chord sounding over an F♭ major chord, which occurs during the “Dance of the Adolescents.”
Polychords are notated using a horizontal line between the chords instead of a slash. (The slash was used for slash chords (see Subsection 6.3.1.)
Also note that it is not necessary to specify the inversion of each of the chords in the polychord.
In th example below, Copland voices an A major chord below an E major chord.
In the example below, features chromatically ascending dominant seventh chords in the left hand against a repeating three-chord cycle of G–F–C in the right hand.