Diesis
The diesis (/ˈdaɪəsɪs/ DY-ə-sis; plural dieses) most commonly refers to:
- The difference between two enharmonic notes in a scale. See Diesis (scale theory);
- by extension, 128/125 (≈ 41¢), the augmented comma or lesser diesis;
- rarely, 648/625, the diminished comma or greater diesis;
- by extension, a melodic unit of about the size of 128/125. See Diesis (melodic unit).
In addition, there are a number of archaic usages in Ancient Greek music:
- 256/243, known as the limma today;
- a variety of quartertones.
Normal diesis
The normal diesis (≈ 38.7¢) is an interval size measure defined as one step of 31edo.