Minor Scale

A minor scale in Western music theory includes any scale that contains, in its tonic triad, at least three essential scale degrees: 1) the tonic (or name of the scale), 2) a minor-third, or an interval of a minor third above the tonic, and 3) a perfect-fifth, or an interval of a perfect fifth above the tonic, altogether comprising a minor triad on the tonic note. All minor scales differ from major scales in that the third in major scales is a major third, i.e. one semitone higher than the minor third found in minor scales.

While this definition may encompass many scales, the term, in its common use, is usually limited to the natural minor, harmonic minor, and melodic minor scales, as they are used in Western classical music (see major and minor). When two major and minor scales share the same key signature, they are relative keys. The natural minor scale is built from the sixth note of the relative major scale as the starting note. Harmonic minor scales differ from the natural scale in that the seventh note is raised up a semitone. Melodic minor scales raise both the sixth and seventh notes up a semitone when ascending, but when descending, the sixth and seventh notes are flattened, producing the natural minor scale.