Diminished Chords

Diminished triads are chords built from stacked minor-thirds. A diminished triad has three notes: the root of the chord, a note a minor-third above the root, and a note a diminished-fifth above the root. The diminished chord gets its name from this diminished-fifth interval.

Diminished Triad
If we stack another minor-third on top of a diminished triad, we get a diminished-seventh chord. This creates and interval of a diminished-seventh above the root of the chord. This interval is what gives the diminished-seventh chord its name.
Diminished-seventh chord
Diminished-seventh Chord
 If we instead add a major-third on top of a diminished triad we get a half-diminished-seventh chord.
Half-diminished-seventh Chord
Half-diminished-seventh Chord
Diminished chords are usually indicated with the following symbols: “°” or “dim” for diminished triads, “°7” or “dim7” for diminished-seventh chords, “ΓΈ7” or “m7♭5”

Chord symbols for diminished chords
Chord symbols for diminished chords
Diminished chords have an unstable sound and usually resolve to a major or minor chord one half-step higher.

Regular resolution of diminished chords
Normal resolution of diminished chords
Diminished chords can also resolve in less common ways, such as the following:

Irregular resolution of diminished chords - 1
Irregular resolution of diminished chords - 2
Other resolutions of diminished chords