In music, a chromatic semitone is the amount by which any note is raised by the addition of a sharp, or lowered by the addition of a flat. In equal temperament, it has a value of exactly 100 cents, or one-twelfth of an octave, and is enharmonic with the diatonic semitone, which is also 100 cents. The two are therefore often conflated, and given the common name of semitone or, in North America, half-step. Figure 1. ... Figure 1. ... Equal temperament is a scheme of musical tuning in which an interval, usually the octave, is divided into a series of equal steps (equal frequency ratios). ... The cent is a logarithmic unit of measure used for musical intervals. ... In music, an octave (sometimes abbreviated 8ve or 8va) is the interval between one musical note and another with half or double the frequency. ... In music, an enharmonic is a note which is the equivalent of some other note, but spelled differently. ... A minor second is the smallest of three commonly occurring musical intervals that span two diatonic scale degrees; the others being the major second and the augmented second, which are larger by one and two chromatic semitones respectively. ... A semitone (also known in the USA as a half step) is a musical interval. ...

However, in any meantone tuning aside from equal temperament, the chromatic semitone is smaller than the diatonic semitone. In Pythagorean tuning it would be larger, equal to the apotome of 2187/2048 rather than the Pythagorean minor semitone, or limma, of 256/243, which corresponds to the diatonic semitone. Hence using it in connection with Pythagorean intervals invites confusion, and the word is not generally used in such cases, being reserved for meantone intonation. Meantone temperament is a system of musical tuning. ... Equal temperament is a scheme of musical tuning in which an interval, usually the octave, is divided into a series of equal steps (equal frequency ratios). ... Pythagorean tuning is a system of musical tuning in which the frequency relationships of all intervals are based on the ratio 3:2. ... Apotome may mean one of the following: In mathematics, apotome is the difference of two quantities that are commensurable only in power. ... The intervals of Pythagorean tuning are just intervals involving only powers of two and three. ...

For intervals in just intonation, the just chromatic semitone of 25/24 the septimal chromatic semitone of 21/20, and the major chroma of 135/128 can be equated with the chromatic semitone. In music, just intonation, also called rational intonation, is any musical tuning in which the frequencies of notes are related by whole number ratios; that is, by positive rational numbers. ...

The chromatic semitone is the amount by which any minor interval needs to be expanded to become major, or by which any major interval is reduced to become minor . For any perfect interval, sharpening of its upper note (or flattening of its lower note) by a chromatic semitone leads to the augmented version of the interval. Similarly flattening of the upper note (or sharpening of its lower note) leads to the diminished version of the interval. For this reason, the chromatic semitone is sometimes called an augmented unison or augmented prime. In music theory, an interval is the relationship between two notes or pitches, the lower and higher members of the interval. ... In music theory, an interval is the relationship between two notes or pitches, the lower and higher members of the interval. ... In music theory, an interval is the relationship between two notes or pitches, the lower and higher members of the interval. ... In music and music theory augmentation is the lengthening or widening of rhythms, melodies, intervals, chords. ... Diminution, from Italian diminuimento, is a musical term used to mean different things in the context of melodies and intervals or chords. ...

See also

• List of meantone intervals
• List of musical intervals
• Augmentation
• Diminution