semitono

Seemitono is the smallest interval used in the standard Western tonal music system. In the common 12-tone equal temperament, an octave is divided into 12 semitones, and one semitone equals 100 cents. The semitone is the distance between two adjacent pitch classes, such as those on a piano keyboard.

There are two kinds of semitones in traditional theory. The diatonic semitone occurs between two notes with adjacent letter names within a diatonic scale, for example E–F and B–C. The chromatic semitone occurs between notes that share the same letter name but are altered by accidentals, such as C–C♯ or F–F♭. These distinctions help describe how scales and chords are formed in different tunings.

In a major scale, semitones appear between the third and fourth degrees and between the seventh and eighth degrees (for example in C major, E–F and B–C). All other steps in the scale are whole tones (two semitones).

Beyond 12-tone temperament, the size of a semitone can vary in other tunings. Some historical and microtonal systems subdivide the octave into more or fewer parts, or use different accidentals and intervallic structures, leading to semitone sizes that differ from the 100-cent standard.

The term semitone is widely used in music theory, pedagogy, and performance to describe pitch distance, tuning, and the construction of scales and harmony.