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Chord Progression.jpg


Originally cord , aphetic form of accord



A chord in music is any harmonic set of two–three or more notes that is heard as if sounding simultaneously. These need not actually be played together: arpeggios and broken chords may for many practical and theoretical purposes be understood as chords. Chords and sequences of chords are frequently used in modern western, west African and Oceanian music, whereas they are absent from the music of many other parts of the world.

The most frequently encountered chords are triads, so called because they consist of three distinct notes: further notes may be added to give seventh chords, extended chords, or added tone chords. The most common chords are the major and minor triads and then the augmented and diminished triads. The descriptions "major", "minor", "augmented" and "diminished" are sometimes referred to collectively as chordal "quality". Chords are also commonly classed by their root note so, for instance, the chord C Major may be described as a triad of major quality built upon the note C. Chords may also be classified by inversion, the order in which their notes are stacked.

However, since the structural meaning of a chord depends exclusively upon the degree of the scale upon which it is built, chords are usually analysed by numbering them, using Roman numerals, upwards from the key-note (See diatonic function). There are four common ways of notating or representing chords in western music other than conventional staff notation; Roman numerals, figured bass, much used in the Baroque era, macro symbols, sometimes used in modern musicology, and various systems of symbols and notations such as are typically found in the lead sheets, fake books and chord charts used in jazz and popular music to lay out the harmonic groundplan of a piece so that the musician may improvise a part.[1]