Chord symbols play important roles in popular, folk, and jazz music. A chord symbol is a letter and/or accidental which indicates a root pitch on which a chord is to be built and other symbols which indicate the chord quality. Most contemporary sheet-music, lead sheets, and fake books contain melodies with chord symbols written above them. Many folk songs are written with words only and chord symbols above the words. Musicians use the chord symbols to improvise accompaniments to the given melody.
In the following example of the song "Rock-a-My Soul" the words are written with the chord symbols C and G7 placed above certain words. The C means that a C major triad is to accompany the words below it and the G7 means that a G major-minor seventh chord is to accompany the words below it. Click the play button and listen to the example.
A capital letter of the musical alphabet by itself or with an accidental indicates a major triad with that note as the root. Bb means a B-flat major triad and G# means a G-sharp major triad. Sometimes a capital M or the abbreviation "maj" will follow the root indicator. For a minor triad a lower case m will follow the root indicator. Sometimes the abbreviation "min" will be used or even the minus sign (-). A "o" or the abbreviation "dim" is used to indicate diminished and a "+" sign or the abbreviation "aug" is used to indicate augmented. Refer to the triad chart below for examples of chord symbols of triads with C as the root. The use of chord symbols has not been standardized; therefore, more than one symbol can be used to indicate a chord. The most frequently used chord symbols are listed first.
The number 7 is added to a chord symbol to indicate a seventh chord. A capital letter by itself with a 7 indicates a major-minor seventh chord. A capital "M" or the abbreviation "maj" indicates that a major-major seventh chord is called for. A lower case "m" or the abbreviation "min" indicates a minor-minor seventh chord. The symbol "o" before the 7 or the abbreviation "dim" indicates a diminished-diminished seventh chord. For a diminished-minor seventh chord a slash is often drawn through the "o" or the symbol "b5" will follow the 7. The b5 means to lower the fifth of a minor chord by one-half step thus making a diminished chord. Refer to the seventh chord chart below.
Triad Symbol Chart
Triad Quality Chord Symbols Chord Spelling Major C Cmaj CM C, E, G Minor Cm Cmin C- C, Eb, G Diminished Cdim Co C, Eb, Gb Augmented Caug C+ C+5 C, E, G#
The following example of the song "Autumn Leaves" shows a written melody with chord symbols. A guitarist would use the chord symbols to improvise an accompaniment to the melody. In this example the guitarist strums an A minor-minor seventh chord, a D major-minor seventh chord, a G major-major seventh chord, and a C major-major seventh chord. The symbol F#m7b5 means to play a F# diminished-minor seventh chord. The b5 does not mean to play a Cb but to lower the C# of an F# minor triad a half-step to C natural. The chord is spelled F#, A, C, E. Finally a B major-minor seventh chord is followed by an Em triad.
Seventh Chord Symbols
7th Chord Quality Chord Symbols Chord Spelling Major-Major CM7 Cmaj7 C, E, G, B Major-Minor C7 C, E, G, Bb Minor-Minor Cm7 Cmin7 C-7 C, Eb, G, Bb Diminished-Minor CØ7 Cm7b5 C, Eb, Gb, Bb Diminished-Diminished Cdim7 Co7 C, Eb, Gb, Bbb
The following arrangement of "We Three Kings" shows how specific bass notes in an accompaniment can be indicated. Both the G chords in the second staff contain a slash followed by another letter. The first letter means the chord and the letter after the slash refers to the desired bass note. In this case the first G would be played with B as the bass note and the second G would be played with a B flat as the bass. Notice that the bass line is descending chromatically (C-B-Bb-A) beginning with the C major triad and ending on the A7 major-minor seventh chord. This provides a contrast to the melody which is rising by steps. Listen to the example and pay close attention to the second staff and the movement of the bass notes.
The following chart shows how other seventh chords can be written. These chords are not as common as the above chords.
7th Chord Quality Chord Symbols Chord Spelling Minor-Major Cm+7 Cmin+7 C, Eb, G, B Augmented-Minor Caug7 C+7 C7+5 C7#5 C, E, G#, Bb Augmented-Major C+M7 C, E, G#, B Major-Minor
C7b5 C, E, Gb, Bb