Chord (music)

In music and music theory, a chord (from the middle English cord, short for accord) is three or more different notes or pitches sounding simultaneously, or nearly simultaneously, over a period of time. For example, if you simultaneously play any three (or more) keys of a piano, you have just played a chord. Likewise, if you simultaneously play three or more strings of a guitar, you have just played a chord on the guitar. Every chord is given a specific name, based on the notes that constitute the chord and the distances, or intervals, between them.

Harmonic analysis and construction

Chords are named for how many notes they contain, more commonly for what type of intervals they are constructed from, and by the root note and bass note.

Related Topics:
Interval - Root note - Bass note

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The easiest way to name a chord, or limit its construction, is according to the number of notes included. The simplest and possibly most frequently used chords are trichords, meaning they have three ("tri") notes (before any doubling of notes, that is), four notes being a tetrachord, six a hexachord, etc.

Related Topics:
Trichord - Tetrachord - Hexachord

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It is more informative to label a chord based on what type of intervals it contains, rather than how many notes, because no matter how many notes a similar interval apart you stack on top of each other, the chord still retains a characteristic sound. The chords most traditionally used in Western music are those with notes fundamentally a third apart (that is, before any inversions and doublings, discussed below), called tertian chords. Chords constructed from seconds are secundal, and from fourths are quartal.

Related Topics:
Third - Tertian - Second - Secundal - Fourth - Quartal

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Chords are also distinguished and notated by the scale degree, pitch, or note of their root and bass, although there are many different conventions for indicating the quality of the chord, and the inversion of the chord (determined by which note of the chord serves as the bass note); see Inverted Triads below). For example, since the first scale degree of the C major scale is the note C, a triad built on top of the note C would be called the one chord, which might be notated 1, I, or even C, in which case the assumption would be made that the key signature of the particular piece of music in question would indicate to the musician what function a C major triad was fulfilling, and that any special role of the chord outside of its normal diatonic function would be inferred from the context.

Related Topics:
Bass note - Inverted Triads - Key signature

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Chords are labelled with chord symbols.

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