Chord (music)

This article is about pitch simultaneity and harmony in music. For other uses, see Chord (disambiguation).

When musicians play three or more different notes at the same time, this creates a chord. In Western music, including classical music, pop music, rock music and many related styles, the most common chords are triads– three notes usually played at the same time. The most commonly used chords are the major chord and the minor chord. An example of a major chord is the three pitches C, E and G. An example of a minor chord is the three pitches A, C and E. (Pictured is a guitar player performing a G7 chord on a guitar).

A chord, in music, is any harmonic set of usually three or more notes (also called "pitches") that is heard as if sounding simultaneously. In everyday use by musical ensembles such as bands and orchestras, the three or more notes of a chord are often sounded together. However, the notes of a chord do not have to be played together at the same time: arpeggios and broken chords (these involve the notes of the chord played one after the other, rather than at the same time) may, for many practical and theoretical purposes, also constitute chords. Chords and sequences of chords are frequently used in modern West African, Oceanian and Western classical music and Western popular music, whereas they are absent from the music of many other parts of the world. In tonal Western classical music (music with a tonic key or "home key"), the most frequently encountered chords are triads, so called because they consist of three distinct notes: the root note, a third above the root note and a fifth interval above the root note. Further notes may be added to give tetrads such as seventh chords, of which the most commonly encountered example being the dominant seventh chord, which consists of a root note, the major third, the perfect fifth, and the minor seventh above the root.

Other chords with more than three notes include added tone chords, extended chords and tone clusters, which are used in contemporary classical music, jazz and other genres. Triads commonly found in the Western classical tradition are major and minor chords, with augmented and diminished chords appearing less often. The descriptions major, minor, augmented, and diminished are referred to collectively as chordal quality. Chords are also commonly classified by their root note—for instance, a C major triad consists of the pitch classes C, E, and G. A chord retains its identity if the notes are stacked in a different way vertically; however, if a chord has a note other than the root note as the lowest note, the chord is said to be in an inversion (this is also called an "inverted chord"). While most chords have at least three notes, power chords, which are widely used in rock music, particularly in hard rock and heavy metal music, have just two notes: the root and the fifth (although the root may be doubled with the octave above).

An ordered series of chords is called a chord progression. One example of a widely used chord progression in Western traditional music and blues is the 12 bar blues progression, the simplest versions of which include tonic, subdominant and dominant chords (this system of naming chords is described later in this section). Although any chord may in principle be followed by any other chord, certain patterns of chords are more common in Western music, and some pattern have been accepted as establishing the key (tonic note) in common-practice harmony–notably the movement between tonic and dominant chords. To describe this, Western music theory has developed the practice of numbering chords using Roman numerals which represent the number of diatonic steps up from the tonic note of the scale.

Common ways of notating or representing chords in Western music other than conventional staff notation include Roman numerals, figured bass, macro symbols (sometimes used in modern musicology), and chord charts. Each of these systems is more likely to appear in certain contexts: figured bass notation was used prominently in notation of Baroque music, macro symbols are used in modern musicology, and chord charts are typically found in the lead sheets used in popular music and jazz. The chords in a song or piece are also given names which refer to their function. The chord built on the first note of a major scale is called the tonic chord (colloquially called a "I" or "one" chord). The chord built on the fourth note of a major scale is called the subdominant chord (colloquially called a "IV" chord or "four" chord). The chord built on the fifth degree of the major scale is called the dominant chord (colloquially called a "V chord" or "five" chord). There are names for the chords built on every note of the major scale. Chords can be played on many instruments, including piano, pipe organ, guitar and mandolin. Chords can also be performed when multiple musicians play together in a musical ensemble or when multiple singers sing in a choir and they play or sing three or more notes at the same time.

C Major triad represented in staff notation.
in just intonation
in Equal temperament
in 1/4-comma meantone
in Young temperament
in Pythagorean tuning

Definition and history

Main article: Harmony

Mussorgsky's Pictures at an Exhibition "Promenade", is a piece showing an explicit chord progression.(Nattiez 1990, p. 218)

The English word chord derives from Middle English cord, a shortening of accord in the original sense of agreement and later, harmonious sound. A sequence of chords is known as a chord progression or harmonic progression. These are frequently used in Western music. A chord progression "aims for a definite goal" of establishing (or contradicting) a tonality founded on a key, root or tonic chord. The study of harmony involves chords and chord progressions, and the principles of connection that govern them.

Ottó Károlyi writes that, "Two or more notes sounded simultaneously are known as a chord," though, since instances of any given note in different octaves may be taken as the same note, it is more precise for the purposes of analysis to speak of distinct pitch classes. Furthermore, as three notes are needed to define any common chord, three is often taken as the minimum number of notes that form a definite chord. Hence Andrew Surmani, for example, (2004, p. 72) states, "When three or more notes are sounded together, the combination is called a chord." George T. Jones (1994, p. 43) agrees: "Two tones sounding together are usually termed an interval, while three or more tones are called a chord." According to Monath (1984, p. 37); "A chord is a combination of three or more tones sounded simultaneously," and the distances between the tones are called intervals. However sonorities of two pitches, or even single-note melodies, are commonly heard as implying chords. A simple example of two notes being interpreted as a chord is when the root and third are played, but the fifth is omitted. In the key of C Major, if the music comes to rest on the two notes G and B, most listeners will hear this as a G Major chord.

Since a chord may be understood as such even when all its notes are not simultaneously audible, there has been some academic discussion regarding the point at which a group of notes may be called a chord. Jean-Jacques Nattiez (1990, p. 218) explains that, "We can encounter 'pure chords' in a musical work," such as in the Promenade of Modest Mussorgsky's Pictures at an Exhibition but, "Often, we must go from a textual given to a more abstract representation of the chords being used," as in Claude Debussy's Première Arabesque.

Upper stave: Claude Debussy's Première Arabesque. The chords on the lower stave are constructed from the notes in the actual piece, shown on the upper stave.

In the medieval era, early Christian hymns featured organum (which used the simultaneous perfect intervals of a fourth, a fifth, and an octave), with chord progressions and harmony an incidental result of the emphasis on melodic lines during the medieval and then Renaissance (15-17th centuries).

The Baroque period, the 17th and 18th centuries, began to feature the major and minor scale based tonal system and harmony, including chord progressions and circle progressions. It was in the Baroque period that the accompaniment of melodies with chords was developed, as in figured bass, and the familiar cadences (perfect authentic, etc.). In the Renaissance, certain dissonant sonorities that suggest the dominant seventh occurred with frequency. In the Baroque period the dominant seventh proper was introduced, and was in constant use in the Classical and Romantic periods. The leading-tone seventh appeared in the Baroque period and remains in use. Composers began to use nondominant seventh chords in the Baroque period. They became frequent in the Classical period, gave way to altered dominants in the Romantic period, and underwent a resurgence in the Post-Romantic and Impressionistic period.

The Romantic period, the 19th century, featured increased chromaticism. Composers began to use secondary dominants in the Baroque, and they became common in the Romantic period. Many contemporary popular Western genres continue to rely on simple diatonic harmony, though far from universally: notable exceptions include the music of film scores, which often use chromatic, atonal or post-tonal harmony, and modern jazz (especially circa 1960), in which chords may include up to seven notes (and occasionally more). When referring to chords that do not function as harmony, such as in atonal music, the term "sonority" is often used specifically to avoid any tonal implications of the word "chord".

Triads consist of three notes; the root or first note, the third, and the fifth. For example, the C major scale consists of the notes C D E F G A B: a triad can be constructed on any note of such a major scale, and all are minor or major except the triad on the seventh or leading-tone, which is a diminished chord. A triad formed using the note C itself consists of C (the root note), E (the third note of the scale) and G (the fifth note of the scale). The interval from C to E is of four semitones, a major third, and so this triad is called C Major. A triad formed upon the same scale but with D as the root note, D (root), F (third), A (fifth), on the other hand, has only three semitones between the root and third and is called D minor, a minor triad.

Notation

C Major triad represented in staff notation

Chords can be represented in various ways. The most common notation systems are:

1. Plain staff notation, used in classical music
2. Roman numerals, commonly used in harmonic analysis to denote the scale step on which the chord is built.
3. Figured bass, much used in the Baroque era, uses numbers added to a bass line written on staff (music), to enable keyboard players to improvise chords with the right hand while playing the bass with their left.
4. Macro symbols, sometimes used in modern musicology, to denote chord root and quality.
5. Various chord names and symbols used in popular music lead sheets, fake books, and chord charts, to quickly lay out the harmonic groundplan of a piece so that the musician may improvise, jam, or vamp on it.

Roman numerals

Main article: Roman numeral analysis

The chord progression vi-ii-V-I in the key of C Major. Using lead sheet chord names, these chords could be referred to as a minor-d minor-G Major-C Major. .

While scale degrees are typically represented in musical analysis or musicology articles with Arabic numerals (e.g., 1, 2, 3, etc., sometimes with a "carat" symbol above the numeral), the triads (three-note chords) that have these degrees as their roots are often identified by Roman numerals (e.g., I, IV, V, which in the key of C Major would be the triads C Major, F Major, G Major). In some conventions (as in this and related articles) upper-case Roman numerals indicate major triads (e.g., I, IV, V) while lower-case Roman numerals indicate minor triads (e.g., I for a Major chord and i for a minor chord, or using the Major key, ii, iii and vi representing typical diatonic minor triads): other writers, (e.g. Schoenberg) use upper case Roman numerals for both major and minor triads. Some writers use upper-case Roman numerals to indicate the chord is diatonic in the major scale, and lower-case Roman numerals to indicate that the chord is diatonic in the minor scale. Diminished triads may be represented by lower-case Roman numerals with a degree symbol (e.g., vii°7 indicates a diminished seventh chord build on the seventh scale degree; in the key of C Major, this chord would be b diminished seventh, which consists of the notes B, D, F and G#).

Roman numerals can also be used in stringed instrument notation to indicate the position or string to play. In some string music, the string on which it is suggested that the performer play the note is indicated with a Roman numeral (e.g., on a four-string orchestral string instrument (violin, viola, cello or double bass), I indicates the highest-pitched, thinnest string and IV indicates the lowest-pitched, thickest bass string). In some orchestral parts, chamber music and solo works for string instruments, the composer specifies to the performer which string should be used with the Roman numeral. Alternately, the note name of the string that the composer wishes the performer to use are stated using letters (e.g., "sul G" means "play on the G string").

Figured bass notation

Main article: Figured bass

A bass note with figured bass symbols underneath the staff. The figured bass symbols indicate the intervals the chord-playing musician should play above the bass note. The figure in this illustration indicates that the intervals of a sixth above the bass and a fourth above the bass should be played.

Figured bass or thoroughbass is a kind of musical notation used in almost all Baroque music (ca. 1600-1750), though rarely in music from later than 1750, to indicate harmonies in relation to a conventionally written bass line. Figured bass is closely associated with chord-playing basso continuo accompaniment instruments, which included harpsichord, pipe organ and lute. Added numbers, symbols and accidentals beneath the staff indicate at the intervals to play, the numbers stand for the number of scale steps above the written note to play the figured notes. In the 2010s, some classical musicians who specialize in music from the Baroque era can still perform chords using figured bass notation. In many cases, however, when Baroque music is performed in the 2010s, the chord-playing performers read fully notated chords that have been prepared for the piece by the music publisher. A Baroque part for a chord-playing instrument that has fully written-out chords is called a "realization" of the figured bass part.

In the illustration the bass note is a C, and the numbers 4 and 6 indicate that notes a fourth and a sixth above, that is F and A, should be played, giving the second inversion of the F major triad. If no numbers are written beneath a bass note, this is assumed to indicate the figure 5,3, which calls for a third and a fifth above the bass note (i.e., a root position triad).

Macro analysis

Macro analysis for triads on C.

Main article: Macro analysis

Macro analysis is used by musicologists, music theorists and advanced university music students to analyze songs and pieces. Macro analysis uses upper-case and lower-case letters to indicate the roots of chords, followed by symbols that specify the chord quality.

Tabular notation

Main article: Chord names and symbols (popular music)

In most genres of popular music, including jazz, pop, and rock, a chord name and the corresponding symbol are typically composed of one or more parts. In these genres, chord-playing musicians in the rhythm section (e.g., electric guitar, acoustic guitar, piano, Hammond organ, etc.) typically improvise the specific "voicing" of each chord from a song's chord progression by interpreting the written chord symbols appearing in the lead sheet or fake book. Normally, these chord symbols include:

1. A letter indicating the root note (e.g. C).
2. A symbol or abbreviation indicating the chord quality (e.g. major, maj, M or minor, min, m). [Note: if no chord quality is specified, the chord is assumed to be a major triad by default, except in notation where the arranger uses capital letters for Major chords (e.g., C for C Major) and lower case letters for minor chords (e.g., "c" for C minor).]
3. Number(s) indicating the number of an interval (e.g. seventh, or 7) above the root note. A bare number stands for a perfect or major interval, except for a seventh, which is taken to be minor by default. Or its full name or symbol may be included. (e.g. major seventh, maj7, or M7)
4. Symbols or abbreviations for altered fifths (e.g. diminished fifth, denoted as ♭5 or augmented fifth, denoted as ♯5).
5. An additional interval number (e.g. "add 13" or "add13"), in added tone chords. Thus "C7 add 13" instructs the performer to play a C7 chord (the individual notes C,E,G, B♭) plus an added 13th scale degree (the note A). [Note: The 13th scale degree is just the sixth scale degree an octave higher]

For instance, the name C augmented seventh, and the corresponding symbol Caug7 (which can also be written as C+7) use parts 1 ("C", thus the chord has "C" as the root note), 2 (an augmented fifth above the root note), and 3 (with the seventh scale degree above the root note).

None of these parts, except for the root, directly refer to the notes forming the chord, but to the intervals they form with respect to the root. For instance, Caug7 is formed by the notes C-E-G♯-B♭. However, its name and symbol refer only to the root note C, the augmented (fifth) interval from C to G♯, and the (minor) seventh interval from C to B♭. The interval from C to E (a major third) sets the chord quality (major). A set of decoding rules is applied to deduce the missing information.

Chord qualities are related with the qualities of the component intervals that define the chord. The main chord qualities are:

• Major, and minor.
• Augmented, diminished, and half-diminished.
• Dominant seventh.

Some of the symbols used for chord quality are similar to those used for interval quality:

• m, or min for minor,
• M, maj, or no symbol for major,
• aug for augmented,
• dim for diminished.

The interpretation of chord symbols depends on the genre of music being played. In jazz from the Bebop era or later, major and minor chords are typically voiced as seventh chords even if only "C" or "Cm" appear in the chart. In jazz charts, seventh chords are often voiced with upper extensions, such as the 9th, ♯11th and 13th, even if the chart only indicates "A7". As well, in jazz, the root and fifth are often omitted from chord voicings, except when there is a diminished fifth or an augmented fifth. The root is omitted because the root is played by the bass player.

In cases where two chordal instruments are comping at the same time from a chart, the players have to either listen to each other's voicings, agree on a voicing beforehand, or alternate comping in different choruses. This is done because if the electric guitarist interprets an "A7" chord as "A7 ♭9" (with a B♭) and the Hammond organ player interprets the "A7" as "A9" (with a B natural), the two chords would clash. The interpretation of chord symbols also depends on the taste preferences of the bandleader or singer who is being accompanied. Some bandleaders or singers may prefer alt chords to be interpreted in different ways. One singer may prefer alt chords with ♭9s, while another singer may prefer ♭13s.

In a pop or rock context, however, "C" and "Cm" would almost always be played as triads, with no sevenths. In pop and rock, in the relatively less common cases where songwriters wish a Major 7th chord or a minor 7th chord, they will indicate this explicitly with the indications "CMaj7" or "Cmin7".

In addition, however,

• Δ is sometimes used for major, instead of the standard M, or maj. In some jazz arrangements, the triangle symbol indicates Major 7th
• − is sometimes used for minor, instead of the standard m or min,
• +, or aug, is used for augmented (A is not used),
• ^o, °, dim, is used for diminished (d is not used),
• ^ø, or ^Ø is used for half diminished; in some fake books, the abbreviation "m7 (♭5)" is used as an equivalent symbol
• dom is used for dominant 7th
• alt (or "alt dom") is used in jazz to indicate an altered dominant seventh chord (e.g., a dominant seventh chord with an added altered extension such as ♭9 and/or ♯11)
• 7 is used for dominant 7th, that is a flatted or minor seventh above the root note (if no other information is provided; thus C7, A7, D7 and G7 all indicate dominant seventh chords. However, if "Maj 7" is indicated, this is a regular seventh above the root)
• 7 (♭9) is used to indicate a dominant seven chord with a minor ninth or flatted ninth (e.g., A7 (♭9), which would contain an A7 chord, thus the notes A, C#, E, G, plus B♭, the ♭9. Sometimes this chord is notated "7 (-9)",
• 9 is used for a ninth chord, which in jazz usually includes the dominant 7th as well, if it is a dominant chord. A 9th can also be requested for other chord qualities (e.g., A Maj 9, which indicates an A Major chord, the notes A, C♯, E, and G♯ with an added 9th, which is a B, or D min 9, which indicates a D minor triad, thus the notes D, F, A with an added 9th, the note E),
• 13 indicates that the 13th is added to the chord. In jazz, when a number higher than 9th is used, it implies that several other lower numbers are played. Thus for A 13 (also indicated as "A13"), a pianist would play the 3rd, the 7th, 9th and 13th (the 11th is normally omitted unless it is augmented. Roots and perfect fifths are commonly omitted from jazz chord voicings).
• sus 4 (or simply 4) indicates that the third is omitted and the fourth used instead. Other notes may be added to a Sus 4 chord, indicated with the word "add" and the scale degree (e.g., A sus 4 (add 9) or A sus 4 (add 7)).
• sus 2 (or simply 2) indicates that the third is omitted and the second (which may also be called the ninth) is used instead. As with "sus 4", a "sus 2" chord can have other scale degrees added (e.g., A sus 2 (add ♭7) or A sus 2 (add 4))
• /C♯ bass or /C♯ indicates that a bass note other than the root should be played. For example, A/C♯ bass indicates that an A Maj triad should be played with a C♯ in the bass. (Note: in some genres of modern jazz, two chords with a slash between them may indicate an advanced voicing called a polychord, which is the playing of two chords simultaneously--e.g., F/A would be interpreted as an F Major triad played simultaneously with an A Maj triad, that is the notes "F, A, C" and "A, C♯, E". To avoid misunderstanding, the "/C♯ bass" notation can be used).
• 5 in rock, hard rock and metal indicates that a power chord should be played. A power chord consists of the root and the fifth, possibly with the root doubled an octave higher. Thirds and sevenths are not played in power chords. Typically, power chords are played with distortion or overdrive. The "5" notation is not always used to indicate when power chords are used in rock. Determining when to play triads and when to use power chords may also come down to the preferences of the guitarist, bandleader or record producer. If a rock chord progression contains sequences with very rapid chord changes, some or all of these chords may be voiced as power chords (e.g., in the chord progression "C///|F///|G///|Ab Bb B C", the last bar in which there is one chord change per beat would probably be voiced as power chords if performed by a hard rock guitarist).
• 6/9 indicates a chord with the triad, with the sixth and ninth of the chord added
• Unusual chords can be indicated with a sequence of scale degrees and indicated additions or omissions (e.g., C7 (no 5th add 9) or F9 (no 7th add 13)).

Characteristics

Within the diatonic scale, every chord has certain characteristics, which include:

• Number of pitch classes (distinct notes without respect to octave) that constitute the chord.
• Scale degree of the root note
• Position or inversion of the chord
• General type of intervals it appears constructed from—for example seconds, thirds, or fourths
• Counts of each pitch class as occur between all combinations of notes the chord contains

Number of notes

Number of notes	Name	Alternate name
1	Monad	Monochord
2	Dyad	Dichord
3	Triad	Trichord
4	Tetrad	Tetrachord
5	Pentad	Pentachord
6	Hexad	Hexachord
7	Heptad	Heptachord
8	Octad	Octachord
9	Ennead	Nonachord
10	Decad	Decachord

Two-note combinations, whether referred to as chords or intervals, are called dyads. Chords constructed of three notes of some underlying scale are described as triads. Chords of four notes are known as tetrads, those containing five are called pentads and those using six are hexads. Sometimes the terms trichord, tetrachord, pentachord, and hexachord are used—though these more usually refer to the pitch classes of any scale, not generally played simultaneously. Chords that may contain more than three notes include pedal point chords, dominant seventh chords, extended chords, added tone chords, clusters, and polychords.

Polychords are formed by two or more chords superimposed. Often these may be analysed as extended chords; examples include tertian, altered chord, secundal chord, quartal and quintal harmony and Tristan chord). Another example is when G⁷(♯11♭9) (G-B-D-F-A♭-C♯) is formed from G major (G-B-D) and D♭ major (D♭-F-A♭). A nonchord tone is a dissonant or unstable tone that lies outside the chord currently heard, though often resolving to a chord tone.

Scale degree

Roman numeral	Scale degree
I	tonic
ii	supertonic
iii	mediant
IV	subdominant
V	dominant
vi	submediant
viio / ♭VII	leading tone / subtonic

C major scale

In the key of C major the first degree of the scale, called the tonic, is the note C itself, so a C major chord, a triad built on the note C, may be called the one chord of that key and notated in Roman numerals as I. The same C major chord can be found in other scales: it forms chord III in the key of A minor (A-B-C) and chord IV in the key of G major (G-A-B-C). This numbering lets us see the job a chord is doing in the current key and tonality.

Many analysts use lower-case Roman numerals to indicate minor triads and upper-case for major ones, and degree and plus signs ( ^o and ⁺ ) to indicate diminished and augmented triads respectively. Otherwise all the numerals may be upper-case and the qualities of the chords inferred from the scale degree. Chords outside the scale can be indicated by placing a flat/sharp sign before the chord — for example, the chord of E flat major in the key of C major is represented by ♭III. The tonic of the scale may be indicated to the left (e.g. F♯:) or may be understood from a key signature or other contextual clues. Indications of inversions or added tones may be omitted if they are not relevant to the analysis. Roman numerals indicate the root of the chord as a scale degree within a particular major key as follows:

Inversion

Root position, first inversion, and second inversion C major chords , , or . Chord roots (all the same) in red.

Root position, first inversion, and second inversion chords over C bass , , or . Chord roots in red.

Main article: Inversion (music)

In the harmony of Western art music a chord is in root position when the tonic note is the lowest in the chord, and the other notes are above it. When the lowest note is not the tonic, the chord is inverted. Chords that have many constituent notes can have many different inverted positions as shown below for the C major chord:

Bass note	Position	Order of notes	Notation
C	root position	C E G or C G E	5 3 as G is a 5th above C and E is a 3rd above C
E	1st inversion	E G C or E C G	6 3 as C is a 6th above E and G is a 3rd above E
G	2nd inversion	G C E or G E C	6 4 as E is a 6th above G and C is a 4th above G

Further, a four-note chord can be inverted to four different positions by the same method as triadic inversion. For example, a G7 chord can be in root position (G as bass note); first inversion (B as bass note); second inversion (D as bass note); or third inversion (F as bass note). Where guitar chords are concerned the term "inversion" is used slightly differently; to refer to stock fingering "shapes".

Secundal, tertian, and quartal chords

See also: Secundal, Tertian, Quartal and quintal harmony, and Mixed-interval chord

Chord	Component intervals
Secundal	2nd's : major 2nd, minor 2nd
Tertian	3rd's : major 3rd, minor 3rd
Quartal	4th's : perfect 4th, augmented 4th
Quintal	5th's

Quartal chord: C-F-B chord .

Many chords are a sequence of ascending notes separated by intervals of roughly the same size. Chords can be classified into different categories by this size:

• Tertian chords can be decomposed into a series of (major or minor) thirds. For example, the C major triad (C-E-G) is defined by a sequence of two intervals, the first (C-E) being a major third and the second (E-G) being a minor third. Most common chords are tertian.
• Secundal chords can be decomposed into a series of (major or minor) seconds. For example, the chord C-D-E♭ is a series of seconds, containing a major second (C-D) and a minor second (D-E♭).
• Quartal chords can be decomposed into a series of (perfect or augmented) fourths. Quartal harmony normally works with a combination of perfect and augmented fourths. Diminished fourths are enharmonically equivalent to major thirds, so they are uncommon. For example, the chord C-F-B is a series of fourths, containing a perfect fourth (C-F) and an augmented fourth/tritone (F-B).

These terms can become ambiguous when dealing with non-diatonic scales, such as the pentatonic or chromatic scales. The use of accidentals can also complicate the terminology. For example, the chord B♯-E-A♭ appears to be a series of diminished fourths (B♯-E and E-A♭) but is enharmonically equivalent to (and sonically indistinguishable from) the chord C-E-G♯, which is a series of major thirds (C-E and E-G♯).

Harmonic content

The notes of a chord form intervals with each of the other notes of the chord in combination. A 3-note chord has 3 of these harmonic intervals, a 4-note chord has 6, a 5-note chord has 10, a 6-note chord has 15. The absence, presence, and placement of certain key intervals plays a large part in the sound of the chord, and sometimes of the selection of the chord that follows.

A chord containing tritones is called tritonic; one without tritones is atritonic. Harmonic tritones are an important part of Dominant seventh chords, giving their sound a characteristic tension, and making the tritone interval likely to move in certain stereotypical ways to the following chord.

A chord containing semitones, whether appearing as Minor seconds or Major sevenths, is called hemitonic; one without semitones is anhemitonic. Harmonic semitones are an important part of Major seventh chords, giving their sound a characteristic high tension, and making the harmonic semitone likely to move in certain stereotypical ways to the following chord. A chord containing Major sevenths but no Minor seconds is much less harsh in sound than one containing Minor seconds as well.

Other chords of interest might include the

• Diminished chord, which has many Minor thirds and no Major thirds, many Tritones but no Perfect fifths
• Augmented chord, which has many Major thirds and no Minor thirds or Perfect fifths
• Dominant seventh diminished five chord, which has many Major thirds and Tritones and no Minor thirds or Perfect fifths

Triads

Pitch constellations of triads

Main article: Triad (music)

See also: Jazz and pop notation for triads

Triads, also called triadic chords, are tertian chords with three notes. The four basic triads are described below.

	Component intervals		Chord symbol	Notes	Audio
	Third	Fifth
Major triad	major	perfect	C, CM, Cmaj, CΔ, Cma	C E G
Minor triad	minor	perfect	Cm, Cmin, C-, Cmi	C E♭ G
Augmented triad	major	augmented	Caug, C+, C+	C E G♯
Diminished triad	minor	diminished	Cdim, Co, Cm(♭5)	C E♭ G♭

Seventh chords

Pitch constellations of seventh chords.

Main article: Seventh chord

See also: Jazz and pop notation for seventh chords

Seventh chords are tertian chords, constructed by adding a fourth note to a triad, at the interval of a third above the fifth of the chord. This creates the interval of a seventh above the root of the chord, the next natural step in composing tertian chords. The seventh chord built on the fifth step of the scale (the dominant seventh) is the only one available in the major scale: it contains all three notes of the diminished triad of the seventh and is frequently used as a stronger substitute for it.

There are various types of seventh chords depending on the quality of both the chord and the seventh added. In chord notation the chord type is sometimes superscripted and sometimes not (e.g. Dm7, Dm⁷, and D^m7 are all identical).

	Component intervals			Chord symbol	Notes	Audio
	Third	Fifth	Seventh
Diminished seventh	minor	diminished	diminished	Co7, Cdim7	C E♭ G♭ B
Half-diminished seventh	minor	diminished	minor	Cø7, Cm7♭5, C−7(♭5)	C E♭ G♭ B♭
Minor seventh	minor	perfect	minor	Cm7, Cmin7, C−7, C−7	C E♭ G B♭
Minor major seventh	minor	perfect	major	Cm(M7), Cm maj7, C−(j7), C−Δ7, C−M7	C E♭ G B
Dominant seventh	major	perfect	minor	C7, C7, Cdom7	C E G B♭
Major seventh	major	perfect	major	CM7, Cmaj7, CΔ7, CΔ7, CΔ7, Cj7	C E G B
Augmented seventh	major	augmented	minor	C+7, Caug7, C7+, C7+5, C7♯5	C E G♯ B♭
Augmented major seventh	major	augmented	major	C+(M7), CM7+5, CM7♯5, C+j7, C+Δ7	C E G♯ B

Extended chords

Main article: Extended chord

See also: Jazz and pop notation for extended chords

Dominant thirteenth extended chord: C E G B♭ D F A . The upper structure or extensions, i.e. notes beyond the seventh, in red. This chord is just a theoretical illustration of this chord. In practice, a jazz pianist or jazz guitarist would not normally play the chord all in thirds as illustrated. Jazz voicings typically use the third, seventh, and then the extensions such as the ninth and thirteenth, and in some cases the eleventh. The root is often omitted from chord voicings, as the bass player will play the root. The fifth is often omitted if it is a perfect fifth. Augmented and diminished fifths are normally included in voicings.

Extended chords are triads with further tertian notes added beyond the seventh: the ninth, eleventh, and thirteenth chords. After the thirteenth, any notes added in thirds duplicate notes elsewhere in the chord; all seven notes of the scale are present in the chord, so adding more notes does not add new pitch classes. Such chords may be constructed only by using notes that lie outside the diatonic seven-note scale.

	Components				Chord symbol	Notes	Audio
	Chord	Interval(s)
Dominant ninth	dominant seventh	major ninth	-	-	C9	C E G B♭ D
Dominant eleventh	dominant seventh (the third is usually omitted)	major ninth	eleventh	-	C11	C E G B♭ D F
Dominant thirteenth	dominant seventh	major ninth	perfect eleventh (usually omitted)	major thirteenth	C13	C E G B♭ D F A

Other extended chords follow similar rules, so that for example maj9, maj11, and maj13 contain major seventh chords rather than dominant seventh chords, while min9, min11, and min13 contain minor seventh chords.

Altered chords

Main article: Altered chord

Altered chord on C with diminished 5th and minor 7th and 9th.

The third and seventh of the chord are always determined by the symbols shown above (the root cannot be so altered without changing the name of the chord, while the third cannot be altered without altering the chord's quality). Nevertheless, the fifth, ninth, eleventh and thirteenth may all be chromatically altered by accidentals. These are noted alongside the altered element. Accidentals are most often used with dominant seventh chords. Altered dominant seventh chords (C^7alt) may have a minor ninth, a sharp ninth, a diminished fifth or an augmented fifth (see Levine's Jazz Theory). Some write this as C⁷⁺⁹, which assumes also the minor ninth, diminished fifth and augmented fifth (see Aebersold's Scale Syllabus). The augmented ninth is often referred to in blues and jazz as a blue note, being enharmonically equivalent to the minor third or tenth. When superscripted numerals are used the different numbers may be listed horizontally (as shown) or else vertically.

	Components		Chord symbol	Notes	Audio
	Chord	Interval(s)
Seventh augmented fifth	dominant seventh	augmented fifth	C7+5, C7♯5
Seventh minor ninth	dominant seventh	minor ninth	C7-9, C7♭9
Seventh sharp ninth	dominant seventh	augmented ninth	C7+9, C7♯9
Seventh augmented eleventh	dominant seventh	augmented eleventh	C7+11, C7♯11
Seventh diminished thirteenth	dominant seventh	minor thirteenth	C7-13, C7♭13
Half-diminished seventh	minor seventh	diminished fifth	Cø, Cm7♭5

Added tone chords

Main article: Added tone chord

Suspended chord (sus2) and added tone chord (add9) both with D (ninth=second), distinguished by the absence or presence of the third (E♭).

An added tone chord is a triad chord with an added, non-tertian note, such as the commonly added sixth as well as chords with an added second (ninth) or fourth (eleventh) or a combination of the three. These chords do not include "intervening" thirds as in an extended chord. Added chords can also have variations. Thus madd9, m4 and m6 are minor triads with extended notes.

Sixth chords can belong to either of two groups. One is first inversion chords and added sixth chords that contain a sixth from the root. The other group is inverted chords in which the interval of a sixth appears above a bass note that is not the root.

The major sixth chord (also called, sixth or added sixth with the chord notation 6, e.g., "C6") is by far the most common type of sixth chord of the first group. It comprises a major triad with the added major sixth above the root, common in popular music. For example, the chord C6 contains the notes C-E-G-A. The minor sixth chord (min6 or m6, e.g., "Cm6") is a minor triad with the same added note. For example, the chord Cmin6 contains the notes C-E♭-G-A. In chord notation, the sixth of either chord is always assumed a major sixth rather than a minor sixth, however a minor sixth interval may be indicated in the notation as, for example, "Cm(m6)", or Cm^m6.

The augmented sixth chord usually appears in chord notation as its enharmonic equivalent, the seventh chord. This chord contains two notes separated by the interval of an augmented sixth (or, by inversion, a diminished third, though this inversion is rare). The augmented sixth is generally used as a dissonant interval most commonly used in motion towards a dominant chord in root position (with the root doubled to create the octave the augmented sixth chord resolves to) or to a tonic chord in second inversion (a tonic triad with the fifth doubled for the same purpose). In this case, the tonic note of the key is included in the chord, sometimes along with an optional fourth note, to create one of the following (illustrated here in the key of C major):

• Italian augmented sixth: A♭, C, F♯
• French augmented sixth: A♭, C, D, F♯
• German augmented sixth: A♭, C, E♭, F♯

The augmented sixth family of chords exhibits certain peculiarities. Since they are not based on triads, as are seventh chords and other sixth chords, they are not generally regarded as having roots (nor, therefore, inversions), although one re-voicing of the notes is common (with the namesake interval inverted to create a diminished third).

The second group of sixth chords includes inverted major and minor chords, which may be called sixth chords in that the six-three (6/3) and six-four (6/4) chords contain intervals of a sixth with the bass note, though this is not the root. Nowadays this is mostly for academic study or analysis (see figured bass) but the neapolitan sixth chord is an important example; a major triad with a flat supertonic scale degree as its root that is called a "sixth" because it is almost always found in first inversion. Though a technically accurate Roman numeral analysis would be ♭II, it is generally labelled N⁶. In C major, the chord is notated (from root position) D♭, F, A♭. Because it uses chromatically altered tones this chord is often grouped with the borrowed chords but the chord is not borrowed from the relative major or minor and it may appear in both major and minor keys.

	Components			Chord symbol	Notes	Audio
	Chord	Interval(s)
Add nine	major triad	major ninth	-	C2, Cadd9	C E G D
Add fourth	major triad	perfect fourth	-	C4, Cadd11	C E G F
Add sixth	major triad	major sixth	-	C6	C E G A
Six-nine	major triad	major sixth	major ninth	C6/9	C E G A D	-
Mixed-third	major triad	minor third	-	-	C E♭ E G

Suspended chords

Main article: Suspended chord

Sus4 chord on C

A suspended chord, or "sus chord" (sometimes wrongly thought to mean sustained chord), is a chord in which the third is replaced by either the second or the fourth. This produces two main chord types: the suspended second (sus2) and the suspended fourth (sus4). The chords, C^sus2 and C^sus4, for example, consist of the notes C D G and C F G, respectively. There is also a third type of suspended chord, in which both the second and fourth are present, for example the chord with the notes C D F G.

The name suspended derives from an early polyphonic technique developed during the common practice period, in which a stepwise melodic progress to a harmonically stable note in any particular part was often momentarily delayed or suspended by extending the duration of the previous note. The resulting unexpected dissonance could then be all the more satisfyingly resolved by the eventual appearance of the displaced note. In traditional music theory the inclusion of the third in either chord would negate the suspension, so such chords would be called added ninth and added eleventh chords instead.

In modern layman usage the term is restricted to the displacement of the third only and the dissonant second or fourth no longer needs to be held over (prepared) from the previous chord. Neither is it now obligatory for the displaced note to make an appearance at all though in the majority of cases the conventional stepwise resolution to the third is still observed. In post-bop and modal jazz compositions and improvisations suspended seventh chords are often used in nontraditional ways: these often do not function as V chords, and do not resolve from the fourth to the third. The lack of resolution gives the chord an ambiguous, static quality. Indeed, the third is often played on top of a sus4 chord. A good example is the jazz standard, Maiden Voyage.

Extended versions are also possible, such as the seventh suspended fourth, which, with root C, contains the notes C F G B♭ and is notated as C7^sus4 . C^sus4 is sometimes written C^sus since the sus4 is more common than the sus2.

	Components				Chord symbol	Notes	Audio
	Chord	Interval(s)
Sus2	open fifth	major second	-	-	Csus2	C D G
Sus4	open fifth	perfect fourth	-	-	Csus4	C F G
Jazz sus	open fifth	perfect fourth	minor seventh	major ninth	C9sus4	C F G B♭ D

Borrowed chords

Main article: Borrowed chord

Borrowed chords from the parallel minor key are commonly found in the Baroque, Classical and Romantic eras.

A borrowed chord is one from a different key than the home key, the key of the piece it is used in. The most common occurrence of this is where a chord from the parallel major or minor key is used. Particularly good examples can be found throughout the works of composers such as Schubert. For instance, for a composer working in the C major key, a major ♭III chord (e.g., an E♭ major chord) would be borrowed, as this chord appears only in the C minor key. Although borrowed chords could theoretically include chords taken from any key other than the home key, this is not how the term is used when a chord is described in formal musical analysis.

When a chord is analysed as "borrowed" from another key it may be shown by the Roman numeral corresponding with that key after a slash. For example, V/V indicates the dominant chord of the dominant key of the present home-key (the present tonic). The dominant key of C major is G major so this secondary dominant is the chord of the fifth degree of the G major scale, which is D major. If used for a significant duration, the use of the D Major chord may cause a modulation to a new key (in this case to G Major).

Borrowed chords are widely used in Western popular music and rock music. For example, there are a number of songs in E Major which use the ♭III chord (e.g., a G major chord used in an E Major song), the ♭VII chord (e.g., a D major chord used in an E Major song) and the ♭VI chord (e.g., a C major chord used in an E Major song). All of these chords are "borrowed" from the key of E minor.

Sources

• Grout, Donald Jay (1960). A History Of Western Music. Norton Publishing.
• Dahlhaus, Carl. Gjerdingen, Robert O. trans. (1990). Studies in the Origin of Harmonic Tonality, p. 67. Princeton University Press. ISBN 0-691-09135-8.
• Goldman (1965). Cited in Nattiez (1990).
• Jones, George T. (1994). HarperCollins College Outline Music Theory. ISBN 0-06-467168-2.
• Nattiez, Jean-Jacques (1990). Music and Discourse: Toward a Semiology of Music (Musicologie générale et sémiologue, 1987). Translated by Carolyn Abbate (1990). ISBN 0-691-02714-5.
• Norman Monath, Norman (1984). How To Play Popular Piano In 10 Easy Lessons. Fireside Books. ISBN 0-671-53067-4.
• Stanley Sadie and John Tyrrell, eds. (2001). The New Grove Dictionary of Music and Musicians. ISBN 1-56159-239-0.
• Surmani, Andrew (2004). Essentials of Music Theory: A Complete Self-Study Course for All Musicians. ISBN 0-7390-3635-1.

Further reading

• Benward, Bruce & Saker, Marilyn (2002). Music in Theory and Practice, Volumes I & II (7th ed.). New York: McGraw Hill. ISBN 0-07-294262-2.
• Mailman, Joshua B. (2015). "Schoenberg's Chordal Experimentalism Revealed Through Representational Hierarchy Association (RHA), Contour Motives, and Binary State Switching" (PDF). Music Theory Spectrum. 37 (2): 224–252.
• Persichetti, Vincent (1961). Twentieth-century Harmony: Creative Aspects and Practice. New York: W. W. Norton. ISBN 0-393-09539-8. OCLC 398434.
• Schejtman, Rod (2008). Music Fundamentals. The Piano Encyclopedia. ISBN 978-987-25216-2-2.

External links

• Quotations related to Chord (music) at Wikiquote
• Media related to Chords at Wikimedia Commons

• How to Interpret Chord Symbols