The minor chord resembles the major chord except that it has a minor third with a major third on top, while a major chord has a major third with a minor third on top. They both contain fifths because two pitches a major and minor third apart are a fifth apart.
A minor chord in just intonation is tuned in the frequency ratio 15:12:10. In twelve-tone equal temperament (now the most common tuning system in th west), a major chord has 4 semitones between the third and fifth, 3 between the root and third, and 7 between the root and fifth. It is represented by the integer notation 0,3,7. The fifth is only two centss narrower than the just perfect fifth, but the minor third is noticeably different at 15.641 cents smaller.
The minor chord, along with the major chord, is one of the basic building blocks of tonal music and the common practice period. It is considered consonant or stable, only slightly less so than the major chord. A diminished chord is a minor chord with a lowered fifth.
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