1. What is a triad?
A triad is a three-note chord built by stacking thirds. In C major, the notes C-E-G form a C major triad. The bottom note is the root, the middle note is the third, and the top note is the fifth.
2. Major, minor, diminished, and augmented
A major triad has a major third and perfect fifth above the root. A minor triad has a minor third and perfect fifth. A diminished triad has a minor third and diminished fifth. An augmented triad has a major third and augmented fifth.
C-E-G
Bright, stable triad.
C-E♭-G
Darker triad.
C-E♭-G♭
Tense, unstable triad.
C-E-G♯
Wide, floating, unstable color.
3. Inversions
A chord inversion changes which chord tone is lowest. C-E-G is root position. E-G-C is first inversion because the third is in the bass. G-C-E is second inversion because the fifth is in the bass. Inversions help pianists move smoothly between chords.
4. Seventh chords
A seventh chord adds one more third above a triad. Common types include major seventh, dominant seventh, minor seventh, half-diminished seventh, and fully diminished seventh. Seventh chords are important in classical harmony and jazz.