Major and minor are frequently referred to in the titles of compositions in their foreign language form, especially in reference to the key of a piece.
|Minor intervals||Major intervals|
|minor second||major second|
|minor third||major third|
|minor sixth||major sixth|
|minor seventh||major seventh|
The other uses of major and minor, in general, refer to musical structures containing major thirds or minor thirds. A major scale is one whose third degree is a major third above the tonic, while a minor scale has a minor third degree. A major chord or major triad, similarly, contains a major third above the root, whereas a minor chord or minor triad contains a minor third above the root. In Western music, a minor chord, in comparison, "sounds darker than a major chord".
The minor third is considered the hallmark of a minor scale, since the sixth and seventh may be variably raised while the third remains unaltered. Contrastingly, changes of mode, which would involve the alteration of the third, and mode mixture, are often analyzed as relatively minor or trivial changes unless structurally supported as the root and overall key and tonality remains relatively unchanged when compared to, for instance, modulation or transposition. These latter operations are done by moving all intervals up or down a certain constant interval, and does change key, but does not change mode, which requires the alteration of intervals. The use of triads only available in the minor mode, such as the use of A♭-major in C major, is relatively decorative chromaticism, considered to add color and weaken sense of key without entirely destroying or losing it.
In the German theory by or derived from Hugo Riemann, the minor mode is considered the inverse of the major mode, an upside down major scale based on (theoretical) undertones rather than (actual) overtones (harmonics). The "root" of the minor triad is thus considered the top of the fifth, which, in the United States, is called "the" fifth. So in C minor, the tonic root is actually G, and the leading tone is A♭ (a halfstep), rather than, in major, the root being C and the leading tone B (a halfstep). Also, since all chords are analyzed as having a tonic, subdominant, or dominant function, with, for instance, in C, A-minor being considered the tonic parallel (US relative), Tp, the use of minor mode root chord progressions in major such as A♭-major-B♭-major-C-major is analyzed as sP-dP-T, the minor subdominant parallel, the minor dominant parallel, and the major tonic. (Gjerdingen, 1990)
Minor scales are sometimes said to have a more interesting, possibly sadder sound than plain major scales. The minor mode, with its variable sixth and seventh degrees, offers nine notes, in C: C-D-E♭-F-G-A♭-A-B♭-B, over the major mode's seven, in C: C-D-E-F-G-A-B. The interval strength, or lowest possible location in the harmonic series, and thus consonance and "stability", of minor triads is less than that of major, which interprets major as more "stable", a major triad being found in the 4th, 5th, and 6th harmonics of a pitch, while the minor being the 10th, 12th, and 15th. This may explain the Picardy third, the use of a major tonic chord at the very end of a composition in minor, since it would be more stable and thus conclusive. There are two variations of the minor scale: harmonic and melodic. Harmonic minor scales have their 7th note raised a semitone, both ascending and descending. In melodic minor scales, the 6th and 7th note ascending is raised a semitone, and descending, the 6th and 7th notes are normal.