In contrast to a unison or an interval, a chord is any group of 3 or more notes that are played at the same time. Broken chords, also known as arpeggios, are chords which are played one note at a time, but add up to 3 or more notes.

    A unison is a single note, whereas an interval consists of 2 notes of different pitches:

    Intervals occur in 5 classes:

  • Major intervals

  • Minor intervals

  • Diminished intervals

  • Augmented intervals

  • Perfect intervals

     When inverted (turned upside down):

  • A major interval becomes a minor interval
  • A minor intervals becomes a major interval
  • An augmented interval becomes a diminished interval
  • A diminished interval becomes an augmented interval
  • A perfect interval becomes a perfect interval

(Illustration of inverted intervals)

     Chords occur in different qualities. Three note chords are known as triads. There are four types of triads:

  • Major

  • Minor

  • Augmented

  • Diminished

     Major chords (triads) consist of a stack of 2 intervals: a major 3rd on the bottom, and a minor 3rd on top:

(Illustration of major chords - notation)

     Minor chords (triads) consist of a stack of 2 intervals: a minor 3rd on the bottom, and a major 3rd on top:

(Illustration of minor chords - notation)

     Augmented chords (triads) consist of a stack of 2 intervals, both of which are major 3rds:

(Illustration of augmented chords - notation)

     Diminished chords (triads) consist of a stack of 2 intervals, both of which are major 3rds:

(Illustration of diminished chords - notation)

     Chords can be turned upside down: they are known as inversions.

     Chords containing more than 3 notes are termed "extended chords", because they extend beyond the mere triad. There are many extended chords, but here are some of the more common:

  • 6th chords

  • Minor 6th chords

  • 7th chords

  • Major 7th chords

  • 9th chords

  • Major 9th chords (the "major" refers to the major 7th in the 9th chord)

  • 11th chords

  • 13th chords

    (Illustration of extended chords)

    Chords can also be altered through the use of sharps and flats. For example, a 7th chord might be altered by lowering the 5th 1/2 step. It would be notated as a C7-5 chord. Another example would be a flat 9th chord, notated as C-9.

(Illustration of altered chords)

     Chords can also be used on top of a note which is not part of the chord. These are known as "slash chords" because they are notated like this: C/B   F7/G   etc.

(Illustration of slash chords)

     In addition to standard music notation, there is a "shorthand" kind of notation known as chord symbols. They typically are found above a melody line (tune of the song) and instruct the musician as to what chord to use at any given time:

     *It should also be noted that not all musicians agree on the names or symbols for all chords. There is no "authority" that passes down rules for such things; no congress that enacts laws about chords and how they are named. But there is general agreement on perhaps 90% of all chords; only on the more complex chords will you see much disagreement.

     Here are some typical piano 3-note chords (triads):

Chords Chord Piano chord Keyboard chord

     Here are some typical extended chords (4 or more notes):

Extended chords

4-note chord