About Chord

What is a Chord?

A chord is a group of three or more different notes played simultaneously. These notes form a harmonic structure that gives music depth and emotion. Most chords are built by stacking intervals of thirds above a root note. Chords are used to establish tonality, create progressions, and support melodies.

Chord Notation

Chord symbols are a shorthand used in lead sheets and chord charts to represent chords. Each symbol contains a root letter and optional suffixes that define the chord type:

Major: C
Minor: Cm or C-
Dominant 7th: C7
Major 7th: Cmaj7
Minor 7th: Cm7 or C-7
Suspended: Csus2, Csus4
Augmented: Caug or C+
Diminished: Cdim

Seventh Chords

Seventh chords are four-note chords formed by adding a seventh interval above the root. They add harmonic complexity and are widely used in jazz, blues, and classical music. Common seventh chords include:

Chord Type	Symbol	Formula	Example (C root)
Major 7th	Cmaj7	1 - 3 - 5 - 7	C - E - G - B
Dominant 7th	C7	1 - 3 - 5 - ♭7	C - E - G - B♭
Minor 7th	Cm7	1 - ♭3 - 5 - ♭7	C - E♭ - G - B♭
Half-Diminished	Cm7♭5 or Cø	1 - ♭3 - ♭5 - ♭7	C - E♭ - G♭ - B♭
Fully Diminished	C°7	1 - ♭3 - ♭5 - ♭♭7	C - E♭ - G♭ - A

Altered Chords

Altered chords are chords that include tones outside the standard major or minor scale. They often appear in jazz and modern music to introduce tension or color. Types include:

Augmented Chord: Built with a raised fifth (C - E - G#)
Diminished Chord: Built with a lowered third and fifth (C - E♭ - G♭)
Suspended Chords: Replace the third with the second or fourth (Csus2: C - D - G, Csus4: C - F - G)
Altered Dominant: Include raised or lowered fifths or ninths (C7♭9, C7♯5)

Inversions

Chord inversions occur when a note other than the root is played in the bass. This changes the chord's sound and can smooth harmonic transitions. For example:

Root position: C - E - G (C is in the bass)
1st Inversion: E - G - C (E is in the bass)
2nd Inversion: G - C - E (G is in the bass)

Inversions are useful for voice leading and creating melodic bass lines.

Chord Function

In tonal harmony, chords serve different functions depending on their role in a key. The three main functions are:

Tonic (I): Provides a sense of resolution and rest.
Subdominant (IV or ii): Moves away from the tonic and builds toward tension.
Dominant (V or vii°): Creates tension that resolves back to the tonic.

For example, in C major: C (I) → F (IV) → G (V) → C (I) forms a complete and satisfying progression.

Source: Information gathered from verified music theory texts and online education resources. We aim for accuracy and clarity—suggestions are welcome.