Diesis

Diesis is a word with a number of different meanings. A diesis is the difference between two enharmonic notes in a tuning system, or any small difference between two notes in a scale. A diesis is usually understood to not be tempered out, as opposed to a comma, which is tempered out.

More specifically, a diesis may be:

- The difference between a small step and a chromatic semitone in a scale, such as the Pythagorean comma in the diatonic scale.

- The interval 128/125, the difference between 5-limit enharmonic intervals, which is tempered out in augmented temperament.

- An interval of approximately 30 to 60 cents, such as a step of 31edo.

- An aberrisma, a diesis used in a functional context in ternary scales.