What is a chord?
A chord is a single musical object made up of two or more pitches, though traditional music theory commonly restricts the label to three or more distinct notes to form a triad or higher structure. A dyad usually functions as a chord only when it participates in a harmonic progression. Played together, we call it a , and played one after another is called an , arpeggio, or sometimes referred to as a broken chord.
All chords are stacks of intervals, and most chords in Western music are built by stacking thirds. We start with a , then add a , adding another third makes a , the next makes a , then a , an , and finally a .
Chord spelling stops at the thirteenth because stacking six thirds already accounts for every scale degree. Standard harmonic notation identifies unique pitch classes rather than pitch heights, so any extension beyond a thirteenth repeats an existing pitch class and adds no new harmonic information.
Rock guitar's bends our expectations, as it sounds only a root and perfect fifth. Power chords are often doubled at the octave but are also legitimately played as a bare . With no third there is no major or minor quality to hear, which is exactly why it stays clean under heavy distortion.
What is a chord quality?
“Quality” is the word we use to describe which sizes of intervals are stacked where. For example, we call a major third with a minor third on top a , and a minor third with a major third on top is called a . A chord's quality is the same no matter which root it starts on. A and a share no pitches, yet our ears can recognize the same major quality in both.
Complete chord quality reference
Triads & suspensions
| Quality | Symbol | Formula | Listen |
|---|---|---|---|
| Power Chord | 5 | 1 5 8 | |
| Major | maj | 1 3 5 | |
| Minor | m | 1 ♭3 5 | |
| Diminished | dim | 1 ♭3 ♭5 | |
| Augmented | + | 1 3 ♯5 | |
| Major ♭5 | maj ♭5 | 1 3 ♭5 | |
| Suspended Second | sus2 | 1 2 5 | |
| Suspended Fourth | sus4 | 1 4 5 |
Sixths & sevenths
| Quality | Symbol | Formula | Listen |
|---|---|---|---|
| Major Sixth | 6 | 1 3 5 6 | |
| Minor Sixth | m6 | 1 ♭3 5 6 | |
| Dominant Seventh | 7 | 1 3 5 ♭7 | |
| Dominant Seventh Suspended Fourth | 7sus4 | 1 4 5 ♭7 | |
| Major Seventh | maj7 | 1 3 5 7 | |
| Minor Seventh | m7 | 1 ♭3 5 ♭7 | |
| Half-Diminished Seventh | ø | 1 ♭3 ♭5 ♭7 | |
| Diminished Seventh | °7 | 1 ♭3 ♭5 ♭♭7 | |
| Minor-Major Seventh | mM7 | 1 ♭3 5 7 | |
| Augmented Seventh | +7 | 1 3 ♯5 ♭7 | |
| Augmented-Major Seventh | +M7 | 1 3 ♯5 7 |
Extended
| Quality | Symbol | Formula | Listen |
|---|---|---|---|
| Added Ninth | add9 | 1 3 5 9 | |
| Minor Added Ninth | madd9 | 1 ♭3 5 9 | |
| Dominant Ninth | 9 | 1 3 5 ♭7 9 | |
| Major Ninth | maj9 | 1 3 5 7 9 | |
| Minor Ninth | m9 | 1 ♭3 5 ♭7 9 | |
| Six-Nine | 6/9 | 1 3 5 6 9 | |
| Minor Six-Nine | m6/9 | 1 ♭3 5 6 9 | |
| Minor-Major Ninth | mM9 | 1 ♭3 5 7 9 | |
| Dominant Ninth Suspended Fourth | 9sus4 | 1 4 5 ♭7 9 | |
| Dominant Eleventh | 11 | 1 3 5 ♭7 9 11 | |
| Major Eleventh | maj11 | 1 3 5 7 9 11 | |
| Minor Eleventh | m11 | 1 ♭3 5 ♭7 9 11 | |
| Minor-Major Eleventh | mM11 | 1 ♭3 5 7 9 11 | |
| Dominant Thirteenth | 13 | 1 3 5 ♭7 9 13 | |
| Major Thirteenth | maj13 | 1 3 5 7 9 13 | |
| Minor Thirteenth | m13 | 1 ♭3 5 ♭7 9 13 | |
| Minor-Major Thirteenth | mM13 | 1 ♭3 5 7 9 13 | |
| Dominant Thirteenth Suspended Fourth | 13sus4 | 1 4 5 ♭7 9 13 |
Altered
| Quality | Symbol | Formula | Listen |
|---|---|---|---|
| Dominant Seventh Flat Five | 7♭5 | 1 3 ♭5 ♭7 | |
| Dominant Seventh Flat Nine | 7♭9 | 1 3 5 ♭7 ♭9 | |
| Dominant Seventh Sharp Nine | 7♯9 | 1 3 5 ♭7 ♯9 | |
| Dominant Seventh Sharp Eleven | 7♯11 | 1 3 5 ♭7 ♯11 | |
| Dominant Seventh Flat Thirteen | 7♭13 | 1 3 5 ♭7 ♭13 | |
| Dominant Ninth Flat Five | 9♭5 | 1 3 ♭5 ♭7 9 | |
| Dominant Ninth Sharp Five | 9♯5 | 1 3 ♯5 ♭7 9 | |
| Dominant Ninth Sharp Eleven | 9♯11 | 1 3 5 ♭7 9 ♯11 | |
| Dominant Ninth Flat Thirteen | 9♭13 | 1 3 5 ♭7 9 ♭13 | |
| Dominant Eleventh Flat Nine | 11♭9 | 1 3 5 ♭7 ♭9 11 | |
| Dominant Eleventh Sharp Nine | 11♯9 | 1 3 5 ♭7 ♯9 11 | |
| Dominant Thirteenth Flat Nine | 13♭9 | 1 3 5 ♭7 ♭9 13 | |
| Dominant Thirteenth Sharp Nine | 13♯9 | 1 3 5 ♭7 ♯9 13 | |
| Dominant Thirteenth Sharp Eleven | 13♯11 | 1 3 5 ♭7 9 ♯11 13 | |
| Major Seventh Sharp Eleven | maj7♯11 | 1 3 5 7 ♯11 | |
| Major Ninth Sharp Eleven | maj9♯11 | 1 3 5 7 9 ♯11 | |
| Major Thirteenth Sharp Eleven | maj13♯11 | 1 3 5 7 9 ♯11 13 |
Alternate symbols
| Quality | Symbol | Also Written |
|---|---|---|
| Major | maj | M, or no symbol at all |
| Minor | m | min, − |
| Diminished | dim | ° |
| Augmented | + | aug |
| Major Seventh | maj7 | M7, Δ7, Δ |
| Minor Seventh | m7 | min7, −7 |
| Half-Diminished Seventh | ø | ø7, m7♭5 |
| Diminished Seventh | °7 | dim7 |
| Minor-Major Seventh | mM7 | m(maj7), −Δ7 |
| Augmented Seventh | +7 | 7♯5, aug7 |
| Augmented-Major Seventh | +M7 | maj7♯5 |
| Suspended Fourth | sus4 | sus |
| Added Ninth | add9 | add2, 2 |
| Six-Nine | 6/9 | 69 |
| Altered Dominant | 7alt | alt |
| Any Alteration | 7♭9, 13♯11 | often parenthesized: 7(♭9), 13(♯11) |
Why no eleventh?
The formulae above seem to selectively ignore our interval stacking algorithm by leaving the eleventh out of some of the thirteenth chords. The does contain an eleventh, and that is the correct definition of a thirteenth chord. In practice, however, the natural eleventh sits a above the major third and its dissonance with the major third blurs the consonance that gives major chords their identity. Convention resolves the conflict by omitting the natural eleventh in any chord with a major third, unless the symbol explicitly calls for it.
Minor chords do not clash with the natural eleventh, which sits a comfortable above the minor third, but the eleventh in a is usually still optional because a sounds every note of a seven-note scale at once and can start dissolving into a scale cluster.
Major and minor
The most foundational step in chord hearing is learning the difference between and . Though the two triads differ only by one note, that one semitone in the inner voice flips the character of the entire chord. Every other standard chord quality, from diminished and augmented triads to complex dominant, extended, and altered chords, is fundamentally rooted in a major or minor identity. Mastering this core binary creates the perceptual anchor required to navigate all further harmonic color.
It's also common to assign emotional differences to chords and qualities. For example, major is conventionally called bright or stable and minor dark or sad. It's important to recognize that descriptions like these are subjective and can vary from person to person. Whether the minor-equals-sad association is just a convention learned from Western music is a genuinely open research question. Either way, with practice, chords can become immediately distinct, recognized qualitatively rather than reasoned about.
What are chord inversions?
Every chord is named for its root and when the root is also the lowest sounding note, we say the chord is in root position. If any note other than the root is in the lowest position, the chord is inverted. This chord's , , and are all the same major triad, built from the same three notes, each with a different note in the lowest position.
Inversions are named by the chord tone order of the lowest sounding note, so placing the third of a triad in the lowest position creates first inversion, and the fifth in the lowest position creates second inversion. Therefore, the quality of a chord is the same in every inversion, a triad has two inversions, a four-note chord has three inversions, and so on. Written music names inversions with a slash. is a C major triad with E in the lowest position, and is the same triad over G. The letter after the slash is simply specifying the lowest sounding note.
What is a chord voicing?
The notes of a chord can appear in any order and in any octave, and the voicing is the specific way the notes are laid out. In a the chord tones are as close together as they can be, all fitting into a single octave. An is when the notes of a chord are spread beyond an octave, leaving gaps wide enough to fit another chord tone between them. When an open voicing spans multiple registers or splits between instrument hands, like placing the root in the left hand and clustering the upper structure in the right hand on piano, we call it a compound voicing.
A voicing can also sound the same note in more than one octave, called doubling. A guitarist strumming an open E major chord on all six strings is playing E, B, E, G♯, B, and E. The root appears three times and the fifth twice, yet the chord is still just an E major triad.
Voicings can even place a note in the lowest position that isn't part of the chord at all using the same slash notation we use for inversions. is a C major triad sounded over a D but because D isn't one of the triad's notes, we don't consider it an inversion. Conversely, a is the exact same sounding notes, but because D is the added ninth of Cadd9, we consider it inverted.
Rearranging a chord's notes and adding new notes eventually leads to a phenomenon which can be confusing while listening to chords in isolation: some chords contain the exact set of pitches as a completely different chord. When two chords share the same pitch set built on a different root, we call them harmonic equivalents, and outside of a musical context, we genuinely cannot tell them apart. Giving the same set of notes multiple names might seem like an unnecessary complication, but chords gain their meaning from that missing musical context. The surrounding harmony and movement of the lowest sounding note generally determine which root a chord is actually functioning around.
Diminished, augmented, and suspended
A stacks two minor thirds, and an stacks two major thirds. Both qualities give up the perfect fifth, the most stable interval inside a triad, and our ears register the loss immediately. Stacking major thirds also divides an octave into three equal parts, so every inversion of an augmented triad produces the same shape. is the same pitch set as , and .
Conversely, suspended chords keep the perfect fifth and remove the third, replacing it with a or a . As the name implies, with no third present there is no major or minor quality directly, and suspended chords tend to seem like they're waiting to resolve to the missing third. Sus2 and sus4 are also inversions of each other. Listen to and .
Sixth chords
Suspended chords aren't the only chords that don't stack thirds. A sixth chord adds a major sixth above a major or minor triad. is a C major triad plus A, the major sixth, and is a C minor triad plus the same A. A sixth is the same pitch class as a thirteenth, so a sixth chord is the same as a thirteenth chord stripped of the seventh, ninth, and possible eleventh. The difference between the two is preserved in the chord symbol: “13” implies a seventh and a ninth sounding below the extension, while “6” means the note was added directly to the triad.
What is a dominant chord?
In a musical key, the fifth scale degree is called the dominant, so in C major the dominant is G. Building a four-note chord on the fifth degree of a major scale creates a structure combining a major triad with a minor seventh, which in C major is . In standard notation, a plain “7” always indicates this specific dominant structure, whether or not the chord is currently acting as the fifth degree of the key.
What defines the dominant sound is its internal tension. The tritone between the major third and the minor seventh drives a strong pull toward resolution. The tension we hear inside a plain survives as the chord grows into a or even a . Any quality that keeps that major-third-plus-minor-seventh core belongs to the dominant family.
Sevenths
The quality of a seventh chord is determined by its underlying triad and the interval between the root and seventh. A major triad makes a when paired with a major seventh, and a when paired with a minor seventh. A minor triad makes a when paired with a minor seventh, and a when paired with a major seventh. Augmented triads can also carry a minor seventh to make an or a major seventh to make an . Diminished triads can carry either a minor seventh to make a , or a diminished seventh to make a .
A diminished seventh chord divides an octave into four equal parts, so each of its inversions produces the same shape on a different root just like an augmented triad. A is the same set of pitches as , , and . Minor seventh chords and half-diminished sevenths can also invert to sixth chords, so is the set of pitches as , and shares its pitches with .
Extended chords
Any chord that stacks intervals past the fundamental octave boundary is called an extended chord. Extended chords are built on top of a base seventh chord, taking on that core chord's quality, and named for its highest interval. Every extended chord also implicitly includes the diatonic thirds stacked between its seventh and the extension. Hence, a isn't a new structural formula, but a extended to its ninth.
We use the word “add” in a chord symbol to negate its implied stack, so means a major triad plus a ninth with nothing in between. A closed constructed this way is functionally identical to rather than a separate harmonic equivalent, and the distinction is a naming convention. An added thirteenth preserves the stacking thirds algorithm, whereas a sixth chord avoids the need to negate three implied notes.
Altered chords
An altered chord is a chord that moves the fifth or an extension of a standard chord by a semitone while keeping the functional core intact. Because alterations primarily intensify dominant resolution, most altered chords are dominant and retain their root, major third, and minor seventh. Standalone alterations add specific modifiers to standard chord symbols like , , , , and . Alterations above the base extension imply a standalone addition whereas alterations below the base extension modify that specific interval in the existing chord. A sharp five is also a valid alteration but because it changes the underlying triad into an augmented triad it can be notated as both or .
Enharmonically equivalent alterations require specific naming based on structural role and chord construction. Although ♭5 and ♯11 share the same pitch class, a ♭5 directly replaces the perfect fifth, and a ♯11 layers above a chord that retains or implies its perfect fifth. Similarly, ♯5 and ♭13 share a pitch class, but ♯5 alters the core triad while ♭13 functions as an altered upper extension over a perfect fifth.
Performance contexts often allow flexibility in which specific alterations are voiced, so altered chords frequently use a generic ‘alt’ symbol to indicate that any combination of alterations may be used. This allows for compound sonorities like , which in this case is contains a ♭9, ♯9, ♯11, and ♭13.
Hearing the chord whole, or hearing the notes
There are two ways to listen to a chord, and skilled musicians use both. Holistic listening recognizes chords qualitatively, including block chords, without inspecting the parts. Analytic listening breaks a chord up to hear individual notes, and arpeggios make analytic listening easy, because the notes already arrive in sequence. No published experiment has directly compared arpeggio-first against block-first training of chord qualities, so any ordering advice, including ours, is craft rather than science. Nevertheless, real music rarely waits for us to consider the notes one at a time, and practicing both analytical and holistic listening helps us understand what we're hearing.
What does science say about chords ear training?
There is no randomized controlled trial of chord-quality training. In fact, we know of no controlled study of adults learning chord identification at all. What does exist is a substantial body of adjacent literature, auditory perceptual learning on intervals and pure tones, and every claim in this section is an extrapolation from that literature to chords.
Adults learn. In Little, Cheng & Wright (2019), adults aged 18 to 27 with little formal training improved perfect-fourth identification from 68.9% to 88.2% in three days, and the gains carried over to untrained instruments.
Short, spaced sessions. In Molloy et al. (2012), listeners training about eight minutes a day learned faster early on and reached the same final level as groups doing four times as many trials, an effect the authors attribute to consolidation happening between sessions rather than during them. The ideal session duration can vary by task (Wright & Sabin, 2007), so a fixed daily number should be considered a starting point rather than a rigid requirement. The gap between sessions is not dead time either. Across hundreds of experiments on spaced practice, retention is best at a particular gap length and falls off on both sides of it, and that best gap sits further out the longer we need the skill to last (Cepeda et al., 2006).
Start easy. Perceptual learning is top-down. The reverse-hierarchy account (Ahissar & Hochstein, 2004, developed in vision and adopted across auditory work) predicts that easy-to-difficult progressions outperform starting at the hardest level, and auditory training studies bear that out. Variety has a price, and varying the stimulus slows early acquisition for beginners (Amitay, Hawkey & Moore, 2005). The practical shape is narrow first, then varied, widening starting notes, octaves, and instruments as accuracy stabilizes.
Train for transfer. Auditory learning can be stubbornly specific to the exact sound trained (Wright & Zhang, 2009), and generalization arrives later. In Wright, Wilson & Sabin (2010), gains on trained conditions appeared within days while transfer to untrained conditions could take twice as long. The good news is that once pitch-discrimination learning arrives, it generalizes fairly well across the frequency range (Delhommeau, Micheyl & Jouvent, 2005).
Isolated qualities or real music?
The strongest criticism of only drilling isolated chords is not that it fails but that it's incomplete. Harmonies live inside a key, where a chord has a function, and usually a before, and an after. The criticism is fair, and the most recent synthesis of the pedagogy literature (Kendüzler, 2026) recommends combining contextual training with isolated drills rather than choosing one over the other. Isolated quality recognition builds the vocabulary that functional hearing uses, and hearing a chord's role inside a progression assumes you can hear the chord at all.
Perfect pitch and chords
Chord hearing is mostly part of relative pitch, and one study looked directly at chord-type identification, recognizing a chord's quality pattern as a relative-pitch skill in listeners with and without absolute pitch (Ziv & Radin, 2014). Chords also have a documented history as a route into absolute pitch, and one longitudinal practical report followed young children acquiring AP through chord-identification training (Sakakibara, 2014).