In music or music theory, secundal is the quality of a chord made from seconds, and anything related to things constructed from seconds such as counterpoint. Secundal chords are often referred to more generally as tone clusters, especially when non-diatonic. "[Any] three or more pitches in secundal relationship may correctly be referred to as a tone cluster." Chords which may be considered as built from sevenths, because of musical inversion, are actually secundal. Polychords may create secundal chords.
- Kostka & Payne (1995). Tonal Harmony, p.499. Third Edition. ISBN 0-07-300056-6.