In music, the acoustic scale, overtone scale, Lydian dominant scale, Lydian ♭7 scale, or the Pontikonisian Scale is a seven-note synthetic scale. This differs from the major scale in having an augmented fourth and a minor seventh scale degree. It is the fourth mode of the melodic minor ascending scale. The term "acoustic scale" is sometimes used to describe a particular mode of this seven-note collection (e.g. the specific ordering C–D–E–F♯–G–A–B♭) and is sometimes used to describe the collection as a whole (e.g. including orderings such as E–F♯–G–A–B♭–C–D).