Polychords are chords constructed from two or more separate chords. Composers and improvisers use polychords as a resource for rich and complex sounds in their music. Polychords frequently occur in jazz and modern classical music.
Examples of Polychords:
C Major/E-flat Major:
D Major/B-flat minor: 
C Augmented/G7 Augmented:
C Major/F-sharp Major Polychord - "Petrushka Chord":
This chord was used by composer Igor Stravinsky in his ballet Petrushka.
This chord was used by composer Igor Stravinsky in his ballet Petrushka.Polychord Video:
