Each family is a group of chords sharing the same character. Understand the family — understand hundreds of chords at once.
1-3-5
A major chord contains a major third — that's what creates the bright, stable quality. Foundation of pop and rock.
1-b3-5
A minor chord has a minor third instead of major. This creates a darker, more melancholic quality.
1-3-5-b7
Dominant seventh — a major triad with a minor seventh. Creates tension that wants to resolve. Foundation of blues and jazz.
1-3-5-7
Major seventh — soft, romantic sound. Used in pop and jazz harmony as the I or IV chord.
1-b3-5-b7
Minor seventh — a softer version of minor. Sounds "jazzy" and smooth. ii and iii in major.
1-2-5
In sus2, the third is replaced by a second. The chord "floats" — neither major nor minor. Creates an open sound.
1-4-5
In sus4, the third is replaced by a fourth. Sounds tense and wants to "resolve" into major or minor.
1-b3-b5
The diminished chord contains a tritone. Sounds unstable, dark, and tense. The vii° in major.
1-3-#5
Augmented triad — a major triad with a raised fifth. Mysterious, unstable sound.
1-5
Power chord — root and fifth only, no third. Tonally neutral, powerful with distortion or overdrive.