Major and minor

In Western music, the adjectives major and minor may describe an interval, chord, scale, or key.

Unisons, fourths, fifths, and octaves and their compound interval must be perfect (or, rarely, diminished or augmented).

Minor keys are sometimes said to have a more interesting, possibly darker sound than plain major scales.

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 the sense of key without entirely destroying or losing it.

The table below gives frequency ratios that are mathematically exact for just intonation, which meantone temperaments seek to approximate.

In just intonation, a minor chord is often (but not exclusively) tuned in the frequency ratio 10:12:15 (playⓘ).

In 12 tone equal temperament (12 TET, at present the most common tuning system in the West) a minor chord has 3 semitones between the root and third, 4 between the third and fifth, and 7 between the root and fifth.