In music and music theory a simultaneity succession is a series of different groups of pitches or pitch classes, each of which is played at the same time as the other pitches of its group. Thus, a simultaneity succession is a succession of simultaneities.

Simultaneity succession is a more general term than chord progression or harmonic progression: not all simultaneity successions are harmonic progressions, but most chord progressions are simultaneity successions.

Music theory | Harmony