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.

Related Topics:
Music - Music theory - Accord - Note - Pitches - Piano - Guitar - Intervals

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Originally, a chord simply meant the sounding together of different tones, the resultant of these tones. Broadly, any combination of three or more notes is a chord, although during the common practice period in western music and most popular music some combinations were given more prominence than others. Thus in common usage a chord is only those groups of three notes which are tonal or have diatonic functionality. Chords being directly perceived units, sonorities of two pitches are often interpreted as fragments of three- or four-note chords.

Related Topics:
Common practice period - Tonal - Diatonic functionality

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A chord is then also only the harmonic function of the group of three notes, and it is unnecessary to have all three notes form a simultaneity. Less than three notes may and often do function, in context, as a simultaneity of all notes of chord. One example is a power chord, another is a broken chord or arpeggio, where each note in a chord is sounded one after the other. One of the most familiar broken chord figures is Alberti bass. See accompaniment.

Related Topics:
Simultaneity - Power chord - Broken chord - Arpeggio - Alberti bass - Accompaniment

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Although, as Jean-Jacques Nattiez (1990, p.218) explains, "we can encounter 'pure chords' in a musical work," such as in the following example from the "Promenade" of Modest Mussorgsky's Pictures at an Exhibition:

Related Topics:
Jean-Jacques Nattiez - Modest Mussorgsky - Pictures at an Exhibition

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But "often, we must go from a textual given to a more abstract representation of the chords being used," as in the following example where the chords on the second stave are abstracted from the actual notes written on the first:

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"For a sound configuration to be recognized as a chord, it must have a certain duration." Goldman (1965, p.26) elaborates: "the sense of harmonic relation, change, or effect depends on speed (or tempo) as well as on the relative duration of single notes or triadic units. Both absolute time (measurable length and speed) and relative time (proportion and division) must at all times be taken into account in harmonic thinking or analysis."

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Music is said to be chord-based when the melody is determined by the chords and not by melodic concerns such as modal frames.

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