Definitions
1.NounOne of two parts, equal or unequal, in which a whole tone is divided.
The semitone in 12-tone equal temperament, with frequency ratio of the twelfth root of two.
2.NounThe semitone in 12-tone equal temperament, with frequency ratio of the twelfth root of two.
3.NounAny of the pitches of a chromatic scale.
4.NounAn interval equal to an augmented unison or a minor second, depending on the context and tuning system used.