Chord Dictionary

The Amadeus chord dictionary provides comprehensive information about chord types, their construction, and usage in music.

Chord Categories

Basic Triads

Major Triad

Formula: 1-3-5
Intervals: Root, Major 3rd, Perfect 5th
Example: C (C-E-G)
Sound: Happy, bright, stable
Usage: Most common chord in Western music, used for tonic, subdominant, and dominant functions

Minor Triad

Formula: 1-♭3-5
Intervals: Root, Minor 3rd, Perfect 5th
Example: Am (A-C-E)
Sound: Sad, dark, introspective
Usage: Common in minor keys, creates emotional depth

Diminished Triad

Formula: 1-♭3-♭5
Intervals: Root, Minor 3rd, Diminished 5th
Example: B° (B-D-F)
Sound: Tense, unstable, transitional
Usage: Leading tone chords, passing chords, creating tension

Augmented Triad

Formula: 1-3-♯5
Intervals: Root, Major 3rd, Augmented 5th
Example: C+ (C-E-G♯)
Sound: Mysterious, unsettled, dreamlike
Usage: Chromatic voice leading, whole tone scales, impressionistic music

Seventh Chords

Major Seventh

Formula: 1-3-5-7
Example: Cmaj7 (C-E-G-B)
Sound: Sophisticated, jazzy, smooth
Usage: Jazz standards, bossa nova, R&B, neo-soul

Dominant Seventh

Formula: 1-3-5-♭7
Example: G7 (G-B-D-F)
Sound: Bluesy, tense, needs resolution
Usage: V7 chord in major/minor keys, blues progressions

Minor Seventh

Formula: 1-♭3-5-♭7
Example: Dm7 (D-F-A-C)
Sound: Mellow, jazzy, sophisticated minor
Usage: ii7 in major keys, jazz standards, modal music

Half-Diminished Seventh

Formula: 1-♭3-♭5-♭7
Example: Bm7♭5 (B-D-F-A)
Sound: Dark, mysterious, jazz noir
Usage: ii°7 in minor keys, passing chords in jazz

Diminished Seventh

Formula: 1-♭3-♭5-♭♭7
Example: B°7 (B-D-F-A♭)
Sound: Very tense, symmetric, dramatic
Usage: Passing chords, modulation, classical music drama

Extended Chords

Ninth Chords

Major Ninth (maj9)

Formula: 1-3-5-7-9
Example: Cmaj9 (C-E-G-B-D)
Usage: Modern jazz, R&B, neo-soul

Dominant Ninth (9)

Formula: 1-3-5-♭7-9
Example: G9 (G-B-D-F-A)
Usage: Blues, funk, jazz

Minor Ninth (m9)

Formula: 1-♭3-5-♭7-9
Example: Dm9 (D-F-A-C-E)
Usage: Smooth jazz, R&B ballads

Eleventh Chords

Dominant Eleventh (11)

Formula: 1-3-5-♭7-9-11
Example: G11 (G-B-D-F-A-C)
Note: Often omit 3rd to avoid clash
Usage: Funk, fusion, modern jazz

Thirteenth Chords

Dominant Thirteenth (13)

Formula: 1-3-5-♭7-9-11-13
Example: G13 (G-B-D-F-A-C-E)
Usage: Big band jazz, sophisticated pop

Suspended Chords

Sus2

Formula: 1-2-5
Example: Csus2 (C-D-G)
Sound: Open, ambiguous, modern
Usage: Pop, rock, creating ambiguity

Sus4

Formula: 1-4-5
Example: Csus4 (C-F-G)
Sound: Unresolved tension, hymn-like
Usage: Resolution to major, gospel, rock

Altered Chords

Dominant Flat Nine

Formula: 1-3-5-♭7-♭9
Example: G7♭9 (G-B-D-F-A♭)
Sound: Very tense, Spanish/flamenco flavor
Usage: V7 to minor, jazz, flamenco

Sharp Eleven

Formula: 1-3-5-♭7-♯11
Example: G7♯11 (G-B-D-F-C♯)
Sound: Lydian dominant, bright tension
Usage: Jazz, fusion, modal interchange

Chord Inversions

Understanding Inversions

Inversions occur when a note other than the root is in the bass:

Root Position: Root in bass (C/C)
First Inversion: 3rd in bass (C/E)
Second Inversion: 5th in bass (C/G)
Third Inversion: 7th in bass (Cmaj7/B)

Slash Chords

Notation and usage of bass notes:

C/E: C major with E in bass
Am/C: A minor with C in bass
G/B: G major with B in bass (common in pop)

Chord Functions

Tonic Function

Primary: I, vi
Role: Home, stability, rest
Common Progressions: I-IV-V-I

Subdominant Function

Primary: IV, ii
Role: Departure from tonic, preparation
Common Progressions: I-IV-I, ii-V-I

Dominant Function

Primary: V, vii°
Role: Maximum tension, demands resolution
Common Progressions: V-I, V7-I

Common Progressions

Pop/Rock

I-V-vi-IV

Example: C-G-Am-F
Songs: “Let It Be”, “Someone Like You”

I-vi-IV-V

Example: C-Am-F-G
Songs: “Stand By Me”, oldies progression

vi-IV-I-V

Example: Am-F-C-G
Songs: Modern pop variation

Jazz

ii-V-I

Example: Dm7-G7-Cmaj7
The fundamental jazz progression

I-vi-ii-V

Example: Cmaj7-Am7-Dm7-G7
Rhythm changes A section

iii-vi-ii-V

Example: Em7-Am7-Dm7-G7
Extended jazz turnaround

Blues

12-Bar Blues

I-I-I-I-IV-IV-I-I-V-IV-I-V
Example: C-C-C-C-F-F-C-C-G-F-C-G

8-Bar Blues

I-I-IV-IV-V-IV-I-V
Shortened blues form

Voice Leading

Smooth Voice Leading

Principles for chord connections:

Minimal Motion: Move voices by smallest intervals
Common Tones: Keep shared notes stationary
Contrary Motion: Voices move in opposite directions
Avoid Parallels: No parallel 5ths or octaves

Chord Substitutions

Tritone Substitution

Replace V7 with ♭II7
Example: G7 → D♭7 in key of C
Creates chromatic bass movement

Practical Applications

Chord Recognition Tips

Listen for Bass: Identifies root or inversion
Quality Detection: Major = bright, Minor = dark
Extensions: Jazz sounds = 7ths, 9ths, etc.
Context: Consider key and progression

Chord Construction

Building chords from scales:

Choose Scale: Major, minor, modal
Stack Thirds: Every other note
Add Extensions: 7th, 9th, 11th, 13th
Alter as Needed: ♭5, ♯11, etc.

Practice Exercises

Ear Training

Play major vs. minor triads
Identify chord qualities by ear
Recognise common progressions
Transcribe simple songs

Theory Exercises

Build all chord types in all keys
Write chord progressions
Analyse songs for chord functions
Practice voice leading

Interactive Features

In the Amadeus app, you can:

See fingering diagrams
Transpose to any key
View in context of progressions