Quartal
Glossary
Set Theory
A chord or scale is quartal if it can be constructed by repeatedly stacking fourths (or fifths, since they share an interval class). Quartal harmony refers to harmony that is not tertiary (thirds-based) but based on perfect fourths and nearby intervals (major thirds, tritones).
See the Quartal index of such set classes of cardinality three through nine.
Set Theory
A chord or scale is quartal if it can be constructed by repeatedly stacking fourths (or fifths, since they share an interval class). Quartal harmony refers to harmony that is not tertiary (thirds-based) but based on perfect fourths and nearby intervals (major thirds, tritones).
See the Quartal index of such set classes of cardinality three through nine.