## 10. Chords: Triads and Sevenths

A chord is three or more notes sounded together; stack two thirds and you have a triad, stack a third third and you have a seventh chord, and the symbol printed above the staff is shorthand for which of them to play.

Source: https://musictheory.center/course/chords
Level: Intermediate · Harmony · 6 sections
Before this: Intervals, Scales: Major and Minor

### Stacking Thirds

https://musictheory.center/course/chords#stacking-thirds

> Play the first one. A single note, then a second note joins it, then a third, and nothing ever leaves. Now play the second one, built the same way out of notes that are next-door neighbours instead. One of the two stops sounding like separate notes and starts sounding like one thing. Which one?

**Plays:** One note, then a third above, then a third above that (C4 E4 G4) · One note, then its two neighbours (C4 D4 E4)

Three note heads on one stem, each a line higher than the last: the C on its own short ledger line just below the staff, the E on the bottom line of the staff and the G on the line above it. That picture — three heads on three consecutive lines, or three heads in three consecutive spaces, and never two of them touching — is what a stack of thirds looks like on paper, and it is the shape to look for in any printed chord. The table underneath walks the seven degrees of C major and marks the three the stack took: the first, the third and the fifth, with one note skipped between each pair. The skipped notes are not missing. They are what makes the gaps thirds rather than steps.

| Degree of C major | Note | Taken by the three-note stack? |
| --- | --- | --- |
| 1st | C4 | Yes — the note the stack is built up from |
| 2nd | D4 | No — skipped, which is what turns the first gap into a third |
| 3rd | E4 | Yes — a third above the first |
| 4th | F4 | No — skipped |
| 5th | G4 | Yes — a third above the third, and a fifth above the first |
| 6th | A4 | No — skipped |
| 7th | B4 | No — but it is where the stack arrives next if it keeps going |

**triad**

**Definition.** A chord is three or more notes sounded together, and a triad is a chord of three notes built by stacking thirds: a root, the note a third above it, and the note a third above that.

The two clips are the same size and the same length and they do not sound alike at all. Three neighbours sounded together — C, D and E — stay three separate notes: they are close enough to interfere with one another, and the ear keeps hearing the rub instead of the whole. Skip a note between each pair and the interference goes. C, E and G blend into a single object with a colour, which is why a stack of thirds is the thing harmony is made of and a stack of steps is an effect.

The stack has a bottom, and the bottom has a name. The note the thirds are counted up from is the **root**, and it is what the chord is named after. It is not necessarily the lowest note being played, and it is not necessarily the note the tune is on — it is the note the stack was built from, which is a fact about how the chord is put together rather than about where it happens to sit.

Thirds are also how a chord gets built out of a scale rather than out of thin air. Take any [scale degree](https://musictheory.center/course/scales#scale-degrees), skip the next, take the one after, skip again, take the one after that: every other degree. That procedure run on the seven degrees of a [key](https://musictheory.center/course/keys-and-key-signatures#what-a-key-is) is where [every chord in that key](https://musictheory.center/course/diatonic-harmony#chords-in-a-key) comes from, and it is the whole subject of Chapter 11.

**Good to know**

- (Fact) Stacking thirds is the same operation as taking every other note of a scale. Counting up [C Major](https://musictheory.center/scale/c-major) — C, D, E, F, G, A, B — and keeping the 1st, 3rd and 5th gives C4 E4 G4; the two notes left out, D and F, are exactly what make the two remaining gaps [Major Third](https://musictheory.center/interval/major-third) and [Minor Third](https://musictheory.center/interval/minor-third) rather than steps.
- (Convention) Building chords from thirds is a choice Western harmony made, not a law of sound. Stack fourths instead and you get the quartal harmony that McCoy Tyner and a great deal of film music run on; replace the third with a second or a fourth and you get [Csus2](https://musictheory.center/chord/c-sus2) and [Csus4](https://musictheory.center/chord/c-sus4); leave the third out altogether and you get the two-note [C5](https://musictheory.center/chord/c-5) a guitarist plays. All of those are chords. None of them is a triad.

**You already know this**

- The major third and the minor third from Chapter 5, the only two distances a triad is ever built from — https://musictheory.center/course/intervals#the-twelve-intervals
- Scale degrees from Chapter 7, which is what "every other one" is counting through — https://musictheory.center/course/scales#scale-degrees

**Where this goes**

- Run the same stack on every degree of a key in turn and you have every chord that key contains — https://musictheory.center/course/diatonic-harmony

**In real music**

- The Beatles — “Twist and Shout” — the long rising "aah" before the last verse is one stack of thirds sung a note at a time — one voice, then a third above it, then a third above that — and held until all three are sounding together

**Try it on your instrument:** Play any note on your instrument, then the note two letters up from it, then two letters up again: C, E, G, or D, F, A, or G, B, D. Do it from four different starting notes, and each time play all three together once you have found them.

**Check:** Three notes, sounded together. Were they built by skipping a note between each one, or are they three neighbours with nothing skipped between them?

- Neighbours, nothing skipped **(correct)** — Correct. C, D and E are three consecutive letters with nothing left out. They are close enough to beat against one another, so the ear keeps them apart as three notes instead of fusing them into one sound.
- A note skipped between each one — A stack of thirds from C would be C, E and G, with D and F left out, and it would blend into a single object rather than staying three separate notes. Play the first clip at the top of the section again straight after this one: the difference is not subtle.
- Only two different notes — There were three different notes. What made it hard to count them is that neighbouring notes interfere with one another, which is precisely why harmony is built from thirds and not from steps.

### The Four Triads

https://musictheory.center/course/chords#the-four-triads

> Play all four. Every one of them starts on the same bottom note and every one of them has three notes. Only the middle note and the top note ever move, and never by more than a half step. Two of the four sound settled, as though they could stop there. The other two sound like they are on their way somewhere. Which two are which? The fifth clip plays the four of them straight through, one to a bar, which is the staff below exactly as it is printed.

**Plays:** Wide third, then narrow third (C4 E4 G4) · Narrow third, then wide third (C4 Eb4 G4) · Narrow third, then narrow third (C4 Eb4 Gb4) · Wide third, then wide third (C4 E4 G#4) · All four in turn, one to a bar (C4 E4 G4 Eb4 Gb4 G#4)

The four triads on C, one to a bar, in the order you just heard them, and the fifth clip above plays these four bars as they stand. The note heads never move: every one of these is a head on a line, a head on the next line, a head on the line above that. What changes is the accidentals printed in front of them — nothing in the first bar, a flat on the middle note in the second, flats on the middle and top notes in the third, a sharp on the top note in the fourth. That is the whole of the difference between the four sounds, and it is why they all look like the same shape on the page.

| Triad | Thirds stacked | Notes from C | Symbol | In a word |
| --- | --- | --- | --- | --- |
| Major | A major third, then a minor third | C4 E4 G4 | [C](https://musictheory.center/chord/c-maj) | Bright |
| Minor | A minor third, then a major third | C4 E♭4 G4 | [Cm](https://musictheory.center/chord/c-m) | Dark |
| Diminished | A minor third, then a minor third | C4 E♭4 G♭4 | [Cdim](https://musictheory.center/chord/c-dim) | Tense |
| Augmented | A major third, then a major third | C4 E4 G♯4 | [Caug](https://musictheory.center/chord/c-aug) | Unsettled |

**triad quality**

**Definition.** A triad’s quality is the name it takes from which two thirds it is stacked out of — major, minor, diminished or augmented — and those four are the only possibilities there are.

The arithmetic is short enough to do in your head. Each of the two thirds is either the wide one or the narrow one, so there are four combinations and no more. Wide then narrow is major; narrow then wide is minor; narrow then narrow is diminished; wide then wide is augmented. Nothing else about a triad is free: fix the two thirds and the third note is fixed with them.

The distance between the outer notes follows, and it is what you are really hearing. Major and minor both span [Perfect Fifth](https://musictheory.center/interval/perfect-fifth) from bottom to top, which is the most stable distance there is between two different notes, and that shared frame is why both of them can end a piece. The diminished triad spans [Diminished Fifth](https://musictheory.center/interval/diminished-fifth) and the augmented [Augmented Fifth](https://musictheory.center/interval/augmented-fifth), both a [half step](https://musictheory.center/course/intervals#half-steps-and-whole-steps) off the stable one, and neither will sit still — the ear takes them as a chord bent out of shape and waits for it to spring back.

So the middle note is what separates major from minor, and the top note is what separates both of those from the two restless ones. That is worth practising as a listening habit rather than a calculation: check the outer frame first, and only then ask about the note in the middle.

**Good to know**

- (Fact) The two thirds settle everything else. There is no further choice to make once they are chosen, and there is no fifth combination: two positions and two sizes give four triads, which is why the list is short and closed rather than a selection from something longer.
- (Convention) Calling major "happy" and minor "sad" is a description that has hardened into a habit, not a property of the sound. The association is strong in Western listeners and weak or absent in listeners raised on other repertoires, and any number of cheerful pieces are in minor keys. The words in the last column of the table are labels to hang a memory on, and nothing more.
- (Tendency — common-practice classical, jazz and most Western popular music; film scoring and some twentieth-century concert music use both far more freely, and the augmented triad is a stable object in whole-tone writing) Diminished and augmented triads turn up as places a piece passes through rather than places it stays. A [phrase](https://musictheory.center/course/melody#phrase-antecedent-consequent) can end on a major or a minor triad and sound finished; ending on either of the other two sounds like a question or a cut-off.

**You already know this**

- Quality from Chapter 5 — major, minor, diminished, augmented — the same four words applied to a whole chord rather than to one distance — https://musictheory.center/course/intervals#number-and-quality
- Consonance and dissonance from Chapter 5, which is why two of these four refuse to sit still — https://musictheory.center/course/intervals#consonance-and-dissonance

**Where this goes**

- A major key produces three major triads, three minor ones and exactly one diminished one, and which degree gets which is the same in every key — https://musictheory.center/course/diatonic-harmony

**In real music**

- The Beatles — “Let It Be” — every chord in the verse is a plain three-note one, and the third chord of the first line — the one that lands on the word "trouble" — is the minor among them, which is the whole reason that word sits heavier than the ones around it
- The Beatles — “Oh! Darling” — the very first chord of the record, struck before anyone sings, is an augmented one: it is why the opening sounds like it is being winched upward rather than simply starting

**Try it on your instrument:** Play C, E and G together on your instrument. Lower the middle note a [half step](https://musictheory.center/course/intervals#half-steps-and-whole-steps) and play it again. Now lower the top note as well. Put both back where they started and raise the top note instead. Say which of the four you are on each time before you play it.

[Build the stack, lower a note, and watch the identifier change its name](https://musictheory.center/tools/chord-identifier?n=C%2CEb%2CGb)

**Check:** Three notes together, built up from the same bottom note as the four above. Is the third above that bottom note the wide one or the narrow one?

- The narrow one — minor **(correct)** — Correct. Three half steps from C up to E flat is the narrow third, and the outer notes are still an ordinary perfect fifth, C up to G. A narrow third inside a perfect fifth is a minor triad.
- The wide one — major — The wide third would put E natural in the middle, four half steps above C. What sounded was one half step lower than that, which is the single change that turns bright into dark. Play the first and second clips at the top of the section back to back.
- The wide one, and the top note stretched too — An augmented triad stretches the top note as well as widening the third, so its outer notes are a half step wider than a perfect fifth and it cannot come to rest. This one came to rest perfectly well; it was simply dark rather than bright.

**Check:** Two of the four triads have an ordinary perfect fifth between their outer notes, and two do not. This is one of the two that do not. Which of them is it?

- Augmented — the outer notes too wide **(correct)** — Correct. The third above C is the wide one, E, and so is the third above that, which puts G sharp on top instead of G. Eight half steps from bottom to top is an augmented fifth, a half step wider than the stable one, and the chord floats rather than settles.
- Diminished — the outer notes too narrow — A diminished triad is narrow at both ends: C, E flat, G flat, six half steps from bottom to top. That one sounds compressed and anxious. What sounded here was stretched and weightless — the opposite fault, and the other of the two.
- Major — the outer notes a perfect fifth after all — A major triad does span a perfect fifth, and it comes to rest. This one did not: hold the last sound in your head and try to sing a note that would finish it. Nothing will, because the top note is a half step above where a perfect fifth would put it.

### Inversions

https://musictheory.center/course/chords#inversions

> Play the first three. They use the same three notes every time — not one is added, not one taken away. All that changes is which of the three is at the bottom. Does moving the lowest note change what you hear, and if so, how much of it? The fourth clip plays the three of them straight through, one to a bar, which is the staff below exactly as it is printed.

**Plays:** Lowest note C (C4 E4 G4) · Lowest note E (E4 G4 C5) · Lowest note G (G4 C5 E5) · The three stacks, as written (C4 E4 G4 C5 E5)

The same C major triad three times over, one to a bar. In the first bar the C hangs below the staff on its own short ledger line, with the E on the bottom line and the G on the line above it. In the second bar that ledger-line C has gone and a new head has appeared above the G, in the third space — the same C, moved up an octave rather than removed, which is why the chord now sits wholly inside the staff. In the third bar the same thing has happened again to the E, which reappears in the fourth space. Count the heads in each bar and there are three every time; read their letters and they are C, E and G every time. Only the order from the bottom up has changed, and the fourth clip above plays these three bars as they stand.

| Position | Lowest note | Notes, bottom to top | What a classical score figures it |
| --- | --- | --- | --- |
| Root position | C4 — the root | C4 E4 G4 | Nothing at all: no figure under the bass means root position |
| First inversion | E4 — the third | E4 G4 C5 | 6 |
| Second inversion | G4 — the fifth | G4 C5 E5 | 6/4 |

**chord inversion**

*also called*: a six chord, or a six-four chord (classical figured bass, where the number under the bass counts the interval up to the root: 6 for first inversion, 6/4 for second), a slash chord (lead sheets and popular music, where C/E means the C triad with E at the bottom)

**Definition.** A chord inversion is the same chord standing on a different one of its own notes: take the lowest note, move it up an [octave](https://musictheory.center/course/pitch-and-notes#the-octave), and the chord keeps its name and every one of its notes while its bass changes.

Nothing is added and nothing is lost, which is why the first three clips are still [C](https://musictheory.center/chord/c-maj). The root is still C, because the root is a fact about how the stack was built and not about which note happens to be lowest. A triad has three notes and therefore three positions: root position with the root at the bottom, first inversion with the third at the bottom, second inversion with the fifth at the bottom. A four-note chord has four positions, for the same reason.

The bass note is nonetheless doing most of the work. It is the note the ear uses to locate a chord, so a triad on its third sounds lighter and less final than the same triad on its root, and a triad on its fifth sounds unresolved in a way the other two do not. Inversions are how a composer keeps a [bass line](https://musictheory.center/course/voice-leading#bass-lines-and-inversions) walking smoothly while the harmony above it jumps about: **the point of an inversion is almost always the bass line, not the chord**.

**Good to know**

- (Fact) Inverting changes no note of a chord. All three positions contain C, E and G and nothing else; the only difference is which octave each of them is in, and therefore which of them is lowest.
- (Convention) The slash spelling names a bass note and nothing more. C/E is the C major triad with E at the bottom, not a C chord played over a separate E chord — and the note after the slash is sometimes not in the chord at all, as in C/D, which is a perfectly ordinary sound and not an inversion of anything.
- (Tendency — common-practice classical voice leading and the counterpoint textbooks that codified it) Second inversion is treated as the unstable one: a triad standing on its fifth is usually approached and quit in one of a handful of set ways, most familiarly the chord that lands on the dominant just before a [cadence](https://musictheory.center/course/diatonic-harmony#cadences). First inversion, by contrast, is used freely wherever a bass line wants to step rather than leap.

**You already know this**

- Inverting an interval in Chapter 5, where the lower note moved up an octave and a fifth became a fourth; a chord is inverted the same way, one note at a time — https://musictheory.center/course/intervals#inversion
- The octave from Chapter 2, the distance a note travels when it is taken off the bottom of a stack and put back on the top — https://musictheory.center/course/pitch-and-notes#the-octave
- The three-note stack from the start of this chapter, which is what all three of these still are — https://musictheory.center/course/chords#stacking-thirds

**Where this goes**

- Choosing an inversion is mostly a decision about the bass line, which is what voice leading is the study of — https://musictheory.center/course/voice-leading

**In real music**

- Procol Harum — “A Whiter Shade of Pale” — the organ line under the whole song walks its bass down one step at a time while the chords above barely change, which it can only do by putting a different note of each chord at the bottom
- Journey — “Don’t Stop Believin’” — the second chord of the piano intro puts the middle note of a B major chord in the bass, which is why the four-bar figure walks its bass down — E, D sharp, C sharp, A — instead of leaping about

**Try it on your instrument:** Play C, E and G together on your instrument. Take the C off the bottom and add it back on at the top, then play it again. Do the same with the E. Play all three versions one after another and listen to the lowest note each time rather than the highest.

[Put C on top and see the identifier name the inversion](https://musictheory.center/tools/chord-identifier?n=E4%2CG4%2CC5)

**Check:** F major is spelled F, A, C. Its second inversion puts the fifth of the chord at the bottom. Before you play anything, work out which note that is.

- C **(correct)** — Correct. Counting up the stack from its root — F is the root, A is the third, C is the fifth — puts C at the top, so second inversion is the version standing on C. Spelled from the bottom it is C, F, A, and a lead sheet would print it F/C.
- A — A is F major’s third, so A in the bass is first inversion: figured 6, and written F/A. Second inversion goes one note further up the stack, to the fifth.
- F — F in the bass is root position, which is where the chord started before it was inverted at all. An inversion is defined by the root no longer being the lowest note.

#### Where the figures came from

The numbers under a classical [bass line](https://musictheory.center/course/voice-leading#bass-lines-and-inversions) are the remains of a job that no longer exists. In the seventeenth and eighteenth centuries a keyboard player or lutenist accompanying from a **basso continuo** part was given only a bass line and a scattering of figures, and was expected to improvise the chords above it on the spot — the figures said which intervals to build over each bass note, and everything else, including how many notes to play and in what order, was left to the player.

That is why the numbers count upward from the bass rather than naming the chord. A 6 under a bass note means "there is a note a sixth above this one", which over E gives C, and a player who knows the [key](https://musictheory.center/course/keys-and-key-signatures#what-a-key-is) fills in the G in between without being told. A 6/4 means a sixth and a fourth above the bass, which over G gives E and C. The figures are instructions to a performer, not an analysis.

[Roman-numeral analysis](https://musictheory.center/course/diatonic-harmony#roman-numerals), which Chapter 11 takes up, borrowed the figures a century later and repurposed them as labels: I6 and I64 name inversions of the tonic chord rather than telling anybody what to play. Both systems are still in use, and it is worth knowing that the one that looks like theory started life as a set of shorthand cues scribbled for somebody who had to sight-read.

### Seventh Chords

https://musictheory.center/course/chords#seventh-chords

> Play all five. Each one is a stack you already know from this chapter with one more note added on top, and in three of the five the notes underneath have moved as well. Which of the five sound settled enough to stop on, and which sound as though they are pointing at something that has not arrived yet?

**Plays:** Wide frame, top note high (C4 E4 G4 B4) · Wide frame, top note lowered (C4 E4 G4 Bb4) · Narrow frame, top note lowered (C4 Eb4 G4 Bb4) · Narrow frame, narrowed fifth (C4 Eb4 Gb4 Bb4) · Every third narrow (C4 Eb4 Gb4 Bbb4)

Four note heads on one stem, on four consecutive lines: the three from a triad and one more a third above the top of them. That is the picture for all five chords in the table below — same shape, same four lines, different accidentals in front. The fourth head lands a seventh above the bottom one, which is where the chord gets its name: the number in the symbol counts the distance from the root to the note that was added, not the number of notes in the chord.

| Symbol | Triad, plus a seventh | Notes from C | Where it lives |
| --- | --- | --- | --- |
| [Cmaj7](https://musictheory.center/chord/c-maj7) | Major triad, major seventh | C4 E4 G4 B4 | Home chords in jazz, bossa nova and soul. Warm and settled: almost never a point of tension |
| [C7](https://musictheory.center/chord/c-7) | Major triad, minor seventh | C4 E4 G4 B♭4 | The chord that leads home in classical and jazz alike, and every chord of a twelve-bar blues |
| [Cm7](https://musictheory.center/chord/c-m7) | Minor triad, minor seventh | C4 E♭4 G4 B♭4 | The everyday minor chord of jazz, funk, R&B and modal writing. Smooth rather than mournful |
| [Cm7b5](https://musictheory.center/chord/c-m7b5) | Diminished triad, minor seventh | C4 E♭4 G♭4 B♭4 | The chord that opens a minor-key turn towards home, and the one built on the seventh degree of a major key |
| Cdim7 | Diminished triad, diminished seventh | C4 E♭4 G♭4 B♭♭4 | A chord to pass through rather than to sit on: classical, jazz and older popular song all use it to slide between two others |

**seventh chord**

**Definition.** A seventh chord is a four-note chord made by stacking one more third on top of a triad, which lands a seventh above the root and gives the chord its number.

The number counts an interval, not a quantity. A seventh chord has four notes, and the 7 in its name measures the distance from the bottom of the stack to the note that was added — C up to B, or C up to B flat. That is worth saying because the ninths and elevenths in this chapter’s last section are counted exactly the same way, and none of those numbers is a count of notes either.

Two qualities are now in play rather than one: the quality of the triad underneath, and the quality of the seventh on top. Major triad with a major seventh gives [Cmaj7](https://musictheory.center/chord/c-maj7); major triad with a minor seventh gives [C7](https://musictheory.center/chord/c-7); minor triad with a minor seventh gives [Cm7](https://musictheory.center/chord/c-m7). Two more come from the diminished triad — with a minor seventh it is [Cm7b5](https://musictheory.center/chord/c-m7b5), and with a seventh narrowed one [half step](https://musictheory.center/course/intervals#half-steps-and-whole-steps) further it is Cdim7, whose top note is spelled B double flat because it is still a third above G flat.

The one to learn by ear first is the difference between the first two, because it is a single half step and it changes what the chord wants. [Cmaj7](https://musictheory.center/chord/c-maj7) is at rest. [C7](https://musictheory.center/chord/c-7) contains a diminished fifth between its third and its seventh, E against B flat, and that interval pulls: it is why a dominant seventh sounds like an arrow pointing at the chord a fourth above it, and why blues, which sits on these chords without ever resolving them, sounds permanently in motion.

**Good to know**

- (Fact) A dominant seventh contains [Diminished Fifth](https://musictheory.center/interval/diminished-fifth) between its third and its seventh — E4 against B♭4 — and a major seventh chord does not. That one interval is the whole of the difference in how the two behave, and it is why the same four notes crop up again in Chapter 14 as the engine of chromatic harmony.
- (Convention) A bare number after a letter always means the lowered seventh. [C7](https://musictheory.center/chord/c-7) is a major triad with a **minor** seventh on top; the version with a major seventh has to announce itself as [Cmaj7](https://musictheory.center/chord/c-maj7). It is the single most common misreading of a chord chart, and it is a convention rather than a logic — nothing about the symbol makes it inevitable.
- (Tendency — twentieth- and twenty-first-century Western popular, jazz and folk repertoire) In jazz and R&B the seventh is the default and a bare triad is the marked, deliberately plain choice. In folk, rock, hymnody and most singer-songwriter writing it is the other way round: triads are the ordinary sound and a seventh is added where a chord needs to lean.

**You already know this**

- The major seventh and the minor seventh from Chapter 5, one half step apart, and the only difference between the first two clips above — https://musictheory.center/course/intervals#the-twelve-intervals
- The four triads from earlier in this chapter, each of which is the bottom three notes of one of these five — https://musictheory.center/course/chords#the-four-triads

**Where this goes**

- Add a fourth note to every chord of a major key and the five above are all the kinds you get — no others are possible — https://musictheory.center/course/diatonic-harmony

**In real music**

- The Beatles — “Something” — the first three chords of the verse are the same chord three times with one note walking down inside it — C, then B, then B flat — so the second is a major seventh, the third a dominant seventh, and you can hear the moment the chord starts to lean
- The Beatles — “Can’t Buy Me Love” — the verse is a twelve-bar blues and every chord in it carries a minor seventh, which is what gives the whole thing its edge instead of a hymn-like squareness
- Joseph Kosma — “Autumn Leaves” — the second half of the tune turns minor by going through a half-diminished chord and then a dominant seventh, and that pair is the exact moment the song changes colour

**Try it on your instrument:** Play a three-note stack from any note. Find the note a [whole step](https://musictheory.center/course/intervals#half-steps-and-whole-steps) below the next [octave](https://musictheory.center/course/pitch-and-notes#the-octave) of your starting note and add it on top. Then raise that added note a half step and play it again. Do this from three different starting notes and listen for which version wants to move on.

[Add the seventh you chose and read the chord’s name](https://musictheory.center/tools/chord-identifier?n=C%2CE%2CG%2CBb)

**Check:** A four-note stack on C. Is the note on top a half step below the octave, or a whole step below it?

- A whole step below — C7 **(correct)** — Correct. The top note is B flat, ten half steps above C, and it sits a whole step under the octave. Against the E in the middle it makes the narrowed fifth that gives this chord its pull, which is why it sounded like it was pointing somewhere rather than arriving.
- A half step below — Cmaj7 — A half step below the octave would be B natural, and that chord — Cmaj7 — sounds settled and slightly dreamy rather than restless. Play the first and second clips at the top of the section back to back: one half step, two completely different jobs.
- Neither: the triad underneath was the dark one — The triad underneath was the bright one: C up to E is four half steps, the wide third. What made the chord sound restless was the note on top, not the note in the middle.

### Reading Chord Symbols

https://musictheory.center/course/chords#reading-chord-symbols

> Play all three. Each one is four notes, and each one is printed under two, three or four different names depending on which book you happened to open. Two of the three differ from one another by a single note. Which two?

**Plays:** First of three (C4 E4 G4 B4) · Second of three (C4 Eb4 G4 Bb4) · Third of three (C4 Eb4 Gb4 Bb4)

The third clip, written out: C, E flat, G flat, B flat. Nothing on the staff tells you what to call it, and that is the point of this section. A jazz fake book prints a slashed circle over this bar, a guitar songbook prints four characters and a flat sign, and a classical analysis prints a slashed circle with a seven after it. All three are instructions to play these four note heads. The table lists every spelling you are likely to meet, the tradition each one comes from, and the notes it actually asks for.

- **Read a symbol in this order** — the root letter, then any sharp or flat on the root, then the quality, then the number, then anything added in brackets
- **A bare number always means the lowered seventh** — [C7](https://musictheory.center/chord/c-7) is a major triad with a minor seventh; the major-seventh version has to spell itself out as [Cmaj7](https://musictheory.center/chord/c-maj7)

| Chord | How this site writes it | Also written | Where the other spelling comes from | Notes from C |
| --- | --- | --- | --- | --- |
| Major triad | [C](https://musictheory.center/chord/c-maj) | CM · Cmaj | A bare capital letter is the everyday form; CM and Cmaj appear only where a bare letter would be ambiguous, as in a list of roots or beside a slash bass. A caret here would not mean a triad at all — see the major seventh row | C4 E4 G4 |
| Minor triad | [Cm](https://musictheory.center/chord/c-m) | Cmin · C- | Cm is universal in print; the minus sign is jazz shorthand, quicker to write by hand and standard in hand-copied parts | C4 E♭4 G4 |
| Diminished triad | [Cdim](https://musictheory.center/chord/c-dim) | C° · Co | The small raised circle is the older classical sign; "o" is what a typewriter or a plain keyboard produces instead | C4 E♭4 G♭4 |
| Augmented triad | [Caug](https://musictheory.center/chord/c-aug) | C+ · C+5 | The plus sign is the commonest form in jazz lead sheets and in classical analysis alike; C+5 spells out which degree was raised, and is preferred on charts that already use numbers for altered notes | C4 E4 G♯4 |
| Major seventh | [Cmaj7](https://musictheory.center/chord/c-maj7) | CM7 · Cma7 · C^7 · CΔ · CΔ7 | The triangle is jazz shorthand for "major", and the caret is its ASCII stand-in on anything typed rather than drawn. Both of them mean the major **seventh** and not the plain triad, which is the trap. Most fake books print the seven as well, as CΔ7, and that is the form a reader meets most often | C4 E4 G4 B4 |
| Dominant seventh | [C7](https://musictheory.center/chord/c-7) | Nothing else in common use | The bare number is universal. "Dominant" is a word for describing the chord, not for writing it down | C4 E4 G4 B♭4 |
| Minor seventh | [Cm7](https://musictheory.center/chord/c-m7) | Cmin7 · Cmi7 · C-7 | Cm7 in printed pop and guitar books; the minus sign again on jazz lead sheets | C4 E♭4 G4 B♭4 |
| Half-diminished seventh | [Cm7b5](https://musictheory.center/chord/c-m7b5) | Cø · Cø7 · C-7b5 · Ch7 | Cm7♭5 is the pop and guitar spelling and describes how the chord is built; the slashed circle is the jazz and classical-analysis spelling and names it instead, and in print it almost always carries a seven, as Cø7. The h is German — halbvermindert, half-diminished — and it is what German-language theory and several notation programs produce when the slashed circle is not to hand | C4 E♭4 G♭4 B♭4 |
| Diminished seventh | Cdim7 | C°7 · Co7 | The circle with a seven after it is the classical sign and still the commonest in print; dim7 is what gets typed when the circle is not to hand | C4 E♭4 G♭4 B♭♭4 |
| Suspended fourth | [Csus4](https://musictheory.center/chord/c-sus4) | Csus | The fourth replaces the third rather than joining it, which is why the symbol carries no quality word at all: a sus chord is neither major nor minor | C4 F4 G4 |
| Power chord | [C5](https://musictheory.center/chord/c-5) | Nothing else in common use | Guitar usage: the root and the fifth with the third left out, so the chord takes no side between major and minor and survives distortion. Tab and some session charts say the same thing in words instead — "no 3rd", or "omit 3" — rather than with a symbol of their own | C4 G4 |

**chord symbol**

*also called*: CΔ (jazz lead sheets and hand-copied parts, for the chord this site writes Cmaj7; usually printed CΔ7), Cø (jazz and classical analysis, for the chord this site writes Cm7b5; usually printed Cø7), C- (jazz lead sheets, for the chord this site writes Cm), C°7 (classical notation and still the commonest form in print, for the chord this site writes Cdim7)

**Definition.** A chord symbol is the shorthand that names a chord above the [staff](https://musictheory.center/course/notation#staff-and-clefs) — a root letter, then a suffix for its quality and any added notes — so that a player can build the chord for themselves instead of reading every note of it.

It is a compressed instruction, and what it compresses is exactly this chapter. The letter gives the root the thirds are stacked from. The quality word or sign gives the two thirds. A number says how far the stack was carried. Everything a symbol can tell you, you can now decode: **Cm7♭5** reads as "stack from C, minor triad, add a seventh, and flatten the fifth", which is C, E flat, G flat, B flat.

What the symbol does **not** say is at least as important. It gives no octave, no order, no doubling and no instruction about which notes to leave out. A pianist playing [Cmaj7](https://musictheory.center/chord/c-maj7) with the B at the bottom and a guitarist playing it with no fifth at all are both playing it correctly. The symbol names a chord; the voicing is the player’s.

The awkward part is that there is no single standard. Several traditions wrote these symbols down independently — classical figured bass, jazz copyists working at speed, guitar songbook publishers, music software — and each left its habits behind. The table above is not a list of right and wrong spellings but a translation key, and a working musician reads all of them without noticing.

**Good to know**

- (Convention) Chord symbols are conventions, plural, and not a notation system. The same four notes are genuinely, correctly written CΔ7, CM7, Cma7 and Cmaj7, and no authority prefers one. This site writes [Cmaj7](https://musictheory.center/chord/c-maj7) and [Cm7b5](https://musictheory.center/chord/c-m7b5) because they spell out how the chord is built, which is the more useful form while you are learning; the single-character forms are the more useful once you are sight-reading.
- (Convention) The circle and the slashed circle are not decoration and are not interchangeable. A plain circle is diminished — [Cdim](https://musictheory.center/chord/c-dim) as a triad, Cdim7 with a seventh, where the seventh is narrowed too. A slashed circle is half-diminished: a diminished triad with an ordinary minor seventh, [Cm7b5](https://musictheory.center/chord/c-m7b5). The slash is what tells you only half the chord is diminished.
- (Tendency — jazz fake books, hand-copied parts and the Real Book tradition) Handwritten jazz parts use the single-character forms — Δ, ø, −, ° — because they are faster to draw and take less width above a melody, while printed pop, guitar and worship books spell the same chords out in letters. If a chart looks like it is using a private code, it is usually just a chart that was written by hand.

**You already know this**

- The five sevenths from earlier in this chapter, which are what most of the awkward symbols are naming — https://musictheory.center/course/chords#seventh-chords
- The flat sign from Chapter 4, doing the same job inside the symbol Cm7♭5 that it does in front of a note head — https://musictheory.center/course/notation#accidentals

**Where this goes**

- Roman numerals do the same compressing job one level up, naming a chord by its degree in the key rather than by its letter — https://musictheory.center/course/diatonic-harmony

**In real music**

- Antônio Carlos Jobim — “The Girl from Ipanema” — the chord under the first sung note is printed FΔ in some fake books and Fmaj7 in others, and it is the same four notes on the page either way
- The Kinks — “You Really Got Me” — the two-chord riff that opens it has no third in either chord, which is exactly what the 5 in a symbol like F5 is telling a guitarist

**Try it on your instrument:** Take any chord chart you have — printed, online, or one you remember — and write each symbol out twice: once in the spelling on the page and once in another spelling from the table. Then play four of them on your instrument from the symbol alone, without looking at the notes.

**Check:** A jazz lead sheet has Cø7 printed over the bar. Before you play anything, work out which four notes it is asking for.

- C, E flat, G flat, B flat **(correct)** — Correct. The slashed circle means half-diminished, which this site writes Cm7b5: a diminished triad with an ordinary minor seventh on top. Only the triad is diminished, which is what the slash through the circle is there to tell you.
- C, E flat, G flat, B double flat — B double flat on top would make it a fully diminished seventh, written C°7 or Cdim7 — an unslashed circle. That chord narrows the seventh as well as the fifth, so every third in it is a narrow one.
- C, E, G, B — C, E, G, B is Cmaj7, which shares no accidentals with this chord at all. The circle in a symbol always means something has been narrowed; nothing in Cmaj7 has been.

**Check:** One of the five seventh chords from this chapter, sounded once on C. Which symbol was printed over it?

- Cm7 **(correct)** — Correct. The third is the narrow one, E flat, so the triad is minor; the outer notes of that triad are a plain perfect fifth, C up to G, so nothing has been narrowed beyond the third; and the top note is B flat, a whole step under the octave. Minor triad plus minor seventh is Cm7.
- Cmaj7 — Cmaj7 has the wide third, E natural, and a top note only a half step under the octave. It is the brightest of the five and this was not it — listen again for the middle note, which sat one half step lower than E.
- Cm7b5 — Cm7b5 does have the narrow third you heard, but its fifth is narrowed too, to G flat, which makes the chord feel squeezed and unresolved. This one had an ordinary perfect fifth holding it open, so it sounded smooth rather than anxious.
- Cdim7 — Cdim7 narrows everything: E flat, G flat and B double flat, three equal narrow thirds. It has no resting point at all. What you heard rested comfortably; only its third was narrow.

### Extensions: A First Look

https://musictheory.center/course/chords#extensions-a-first-look

> Play all three. Every one of them is a four-note stack from earlier in this chapter with the stacking carried on past the top: one more note skipped and one more note added, and in the third clip that is done twice over. The bottom note has been dropped an octave in all three so that the top of the stack stays clear — nothing else about the four notes underneath has changed. Does the added note arrive as a new event, or as colour on something that was already there?

**Plays:** Five notes, bright (C3 E4 G4 B4 D5) · Five notes, leaning (C3 E4 G4 Bb4 D5) · Six notes, dark (C3 Eb4 G4 Bb4 D5 F5)

The first clip’s five notes drawn as a stack: root, third, fifth, seventh, ninth, on five consecutive lines and spaces climbing from the ledger-line C below the staff to the D above its top line. That is the stack. What you actually heard is not laid out that way — the clip drops the root a whole octave beneath the rest, which is what a player does with five notes and why it sounds clear rather than thick. Piled into one low octave, three thirds on top of one another arrive as mud; put the root underneath and let the other four breathe above it and every note of the stack is audible. The table gives the three extensions, the note each one adds above C, and the symbols they appear in.

| Extension | The note it adds above C | Symbols it appears in | Same letter as |
| --- | --- | --- | --- |
| Ninth | D5 | [Cmaj9](https://musictheory.center/chord/c-maj9) · [C9](https://musictheory.center/chord/c-9) · [Cm9](https://musictheory.center/chord/c-m9) | The second degree of the scale, an octave higher |
| Eleventh | F5 | [Cm11](https://musictheory.center/chord/c-m11) · [C11](https://musictheory.center/chord/c-11) | The fourth degree of the scale, an octave higher |
| Thirteenth | A5 | [C13](https://musictheory.center/chord/c-13) · [Cmaj13](https://musictheory.center/chord/c-maj13) | The sixth degree of the scale, an octave higher |

**chord extension**

**Definition.** A chord extension is a note added to a seventh chord by carrying the stack of thirds on past the seventh: the ninth, the eleventh and the thirteenth, which are the second, fourth and sixth [degrees of the scale](https://musictheory.center/course/scales#scale-degrees) written an [octave](https://musictheory.center/course/pitch-and-notes#the-octave) higher.

Keep stacking and the numbers keep climbing, because they go on counting from the root through the whole stack rather than restarting at the octave. Above the seventh the next third lands on a ninth, the one after that on an eleventh, the one after that on a thirteenth — and then the stack has used all seven notes of the scale and there is nowhere further to go. That is why the list stops at thirteen.

A ninth and a second are the same letter. D above C is a [Major Second](https://musictheory.center/interval/major-second); the same D an octave higher is a [Major Ninth](https://musictheory.center/interval/major-ninth). Nothing about the note has changed. The number is bigger because it is measuring from the bottom of a stack that now has five notes in it, and because calling it a second would suggest it was sitting next to the root, rubbing against it, which is precisely what it is not doing.

In practice these chords are rarely played complete. A symbol like [C13](https://musictheory.center/chord/c-13) names a six-note chord and a pianist will usually play four of them, keeping the third and the seventh — the two notes that decide what kind of chord it is — and the extension itself, and dropping whatever gets in the way. The symbol is a description of the harmony, not a list of keys to press.

**Good to know**

- (Fact) The numbers count intervals from the root through a continuous stack of thirds, so they run 1, 3, 5, 7, 9, 11, 13 and stop. There is no fifteenth: the next third above a thirteenth is the root again, two octaves up.
- (Convention) A number in a symbol implies everything beneath it. [C13](https://musictheory.center/chord/c-13) is understood to contain a seventh, and usually a ninth, even though the symbol names only the thirteenth. The symbol for a ninth **without** a seventh underneath it is a different one, [Cadd9](https://musictheory.center/chord/c-majadd9), and the word "add" is there precisely to say that the stack was skipped rather than completed.
- (Tendency — jazz, studio and session piano and guitar voicings) The fifth is the first note dropped from an extended chord, and the root is the second, since a bass player is already holding it. A five-note symbol regularly reaches the ear as four notes, and a six-note symbol as four or five.

**You already know this**

- Compound intervals from Chapter 5, where a ninth was defined as an octave plus a second; an extension is the same arithmetic applied to a stack of thirds — https://musictheory.center/course/intervals#compound-intervals
- The seventh from earlier in this chapter, the last rung of the stack before an extension begins — https://musictheory.center/course/chords#seventh-chords

**Where this goes**

- Which extensions a style reaches for, and which it refuses, is a large part of what makes one style sound unlike another — https://musictheory.center/course/contemporary

**In real music**

- Grover Washington Jr. and Bill Withers — “Just the Two of Us” — the two-bar keyboard figure the whole record is built on never plays a plain three-note chord: every chord in the loop carries a seventh and a ninth
- Stevie Wonder — “Isn’t She Lovely” — the chords under the opening harmonica solo are sevenths with ninths on top throughout, and the ninth is the note that makes them glow rather than merely function

**Try it on your instrument:** Play a three-note stack from C. Add the note a [whole step](https://musictheory.center/course/intervals#half-steps-and-whole-steps) below the C above it, and play it again. Now add the note a whole step above that C, and play it a third time. Then do all three steps again starting from G instead.

[Stack the ninth on top and see what the identifier calls it](https://musictheory.center/tools/chord-identifier?n=C3%2CE4%2CG4%2CB4%2CD5)

**Check:** A C major triad, then the same triad with a seventh added, then the same again with a ninth added. Work out which note arrives last before you play it.

- D **(correct)** — Correct. The ninth above C is D — the second degree of C major, moved up an octave — and it arrives on the third playing, on top of a stack that already had its seventh in place.
- B — B arrived second, not last. It is the seventh above C, and a major seventh here rather than a minor one, which makes the finished chord Cmaj9 rather than C9.
- B flat — B flat is the seventh in C9 and in C13, but this stack was the major-seventh one and its seventh is B natural. Either way, the seventh arrives before the ninth: the stack is built from the bottom up.

#### Why you rarely hear an eleventh over a major third

Of the three extensions, the eleventh is the awkward one, and it is awkward over exactly one kind of chord. In C, the eleventh is F and the third is E. Played together in a dominant or major chord they are a [half step](https://musictheory.center/course/intervals#half-steps-and-whole-steps) apart with an [octave](https://musictheory.center/course/pitch-and-notes#the-octave) between them — a minor ninth — and that is the harshest interval in common use. The ear hears it as a mistake rather than a colour, which is why textbooks list the eleventh as an "avoid note" over a major third.

Three ordinary solutions follow, and all three are in constant use. Put the eleventh over a minor chord instead, where the third is E flat and the clash disappears: [Cm11](https://musictheory.center/chord/c-m11) is a staple of modal jazz and of a great deal of soul. Raise the eleventh a half step, giving the sharp eleven of the [lydian](https://musictheory.center/course/modes#the-seven-modes) sound, which is a colour rather than a clash. Or drop the third and let the fourth stand in its place — which is what a suspended chord is, and why [C11](https://musictheory.center/chord/c-11) as tonal spells it contains no third at all.

None of this is a rule handed down. It is a description of what players found sounded good and then kept doing, and composers who wanted the clash — Messiaen, Ravel in places, a good deal of contemporary gospel — have written it deliberately and to great effect. The useful version of the rule is: if an eleventh sounds wrong, check what the third is doing.

### Key Takeaways

https://musictheory.center/course/chords#key-takeaways

- A chord is three or more notes sounded together, and a triad is a chord of three notes built by stacking two thirds on top of one another.
- The two thirds a triad is stacked from decide its quality — major, minor, diminished or augmented — and those four are the only possibilities there are.
- Major and minor triads span a perfect fifth from bottom to top and can end a piece; diminished and augmented triads do not, and generally sound like places a piece is passing through.
- An inversion changes which note of a chord is lowest without changing the chord itself: the same notes, a different bass, and almost always a decision about the bass line.
- A seventh chord is a triad with one more third stacked on top, and the five common ones are the major seventh, the dominant seventh, the minor seventh, the half-diminished and the diminished seventh.
- A bare number in a chord symbol always means the lowered seventh, which is why C7 and Cmaj7 are different chords a single half step apart.
- Chord symbols are several overlapping conventions rather than one standard, so the same four notes are correctly written CΔ7, CM7, Cma7 and Cmaj7 depending on who set the page.
- Extensions carry the same stack of thirds past the seventh to the ninth, eleventh and thirteenth, which are the second, fourth and sixth degrees of the scale an octave higher.

### Questions

**What is the difference between a chord and a triad?**

A chord is any three or more notes sounded together. A triad is one particular kind of chord: exactly three notes built by stacking thirds, so that they are the first, third and fifth [degrees](https://musictheory.center/course/scales#scale-degrees) counted from its own root. Every triad is a chord, and most chords are not triads.

**What does the 7 in C7 mean?**

It means a fourth note has been added a minor seventh above the root — B flat above C — on top of an ordinary C major triad. A bare number in a chord symbol always means the lowered seventh. For the major seventh, B natural, the symbol has to say so: Cmaj7.

**What is a chord inversion?**

It is the same chord standing on a different one of its own notes. Move the lowest note up an [octave](https://musictheory.center/course/pitch-and-notes#the-octave) and nothing is added or removed: C, E, G becomes E, G, C. First inversion stands on the third and second inversion on the fifth, written C/E and C/G on a lead sheet.

**What does Cmaj7 mean, and how is it different from C7?**

Both are a C major triad with a fourth note added on top. Cmaj7 adds B, a [half step](https://musictheory.center/course/intervals#half-steps-and-whole-steps) below the [octave](https://musictheory.center/course/pitch-and-notes#the-octave), and sounds settled and warm. C7 adds B flat, a whole step below, and leans hard towards the chord a fourth above it. One note apart, and opposite jobs.

**How can I tell whether a chord is major or minor?**

Listen to the distance from the lowest note of the stack to the middle one. Four [half steps](https://musictheory.center/course/intervals#half-steps-and-whole-steps) is the wide, bright third of a major chord; three half steps is the narrow, dark third of a minor one. The outer notes are a perfect fifth in both, so the middle note decides it by itself. You can also [name any chord from its notes](https://musictheory.center/tools/chord-identifier) on the spot.

**What is a half-diminished chord?**

It is a diminished triad with an ordinary minor seventh on top: C, E flat, G flat, B flat. Pop and guitar books write it Cm7♭5, and jazz and classical analysis write it Cø7 with a slashed circle. Both spellings ask for exactly the same four notes.

### Other languages

- https://musictheory.center/course/chords/llms.txt
- https://musictheory.center/fr/cours/accords/llms.txt
- https://musictheory.center/es/curso/acordes/llms.txt