What Is a Chord?

A chord is a group of notes heard as one harmony. Most beginners start with a triad, a three-note chord built from a root, a third and a fifth. Count the semitones and build C major one note at a time. Follow the interactive lesson below to learn more.

Lesson 4 of 20 · Interactive

Build a chord, one note at a time

9 steps · sound on

Tap a key

Every note you play sends out its own waves

Build your first chord in 9 short steps.

You press the keys, the piano shows the sound. Start with one note and end up playing every common chord.

Step 1 of 9

Start with one note

Every chord starts with a single note. This one is C, and the rings show its sound spreading out.

Tap the amber key. That is C.

Recap

What you just learned

Steps 1 and 2
A chord is notes heard as one
Three or more notes played together, and your ear hears them as one harmony.
C + E + G = C majorRead the full answer ↓
Step 2
Count keys to build it
From the root, count 4 keys up for the third, then 3 more for the fifth. Black keys count too.
C → 4 → E → 3 → GRead the full answer ↓
Step 3
Every note has a job
The root names the chord, the third makes it major or minor, the fifth holds it together.
root · third · fifthRead the full answer ↓
Step 4
One note turns it minor
Move the third down one key. The root and fifth stay where they are.
C E G → C E♭ GRead the full answer ↓
Steps 5 and 6
Four kinds of triad, in any key
Change the gaps and you change the chord type. Move the root and the shape moves with it.
4+3 · 3+4 · 3+3 · 4+4Read the full answer ↓
Step 7
Any order, same chord
Put E or G at the bottom and it is still C major. Those orders are called inversions.
C E G · E G C · G C ERead the full answer ↓

Chord types

Every chord from step 9, with its own page

Full explanation

Every part of the lesson, answered in full

Open any question to read the full answer.

What exactly is a chord?

Play C, E and G together. Your ear can hear three pitches, but it also groups them into one harmony: a C major chord.

In basic tonal music, the clearest complete chord is a triad. A triad contains three different note names arranged in thirds. More notes can be added to make seventh, ninth and other extended chords.

Two notes together are often called a dyad or simply an interval. Musicians still use two-note power chords and may call them chords in practice. The useful beginner rule is that three different notes give you enough information to identify a full major, minor, diminished or augmented triad.

How do you build a C major chord?

Start on C. This is the root, the note from which you measure.

Count four semitones upward, including every black and white key you pass after C. You land on E. Then count seven semitones upward from C and you land on G.

Play C, E and G together:

C is the root
E is the third, four semitones above C
G is the fifth, seven semitones above C

Use the same distances from another root and you build the same chord type. Four and seven semitones above D give F sharp and A, so D-F sharp-A is D major.

What do the root, third and fifth do?

Each note has its own job. Tap them one by one in step 3 of the lesson above and hear the chord get more specific with each note.

The root - C gives the chord its name and is the note from which every other chord tone is measured.
The third - E makes the chord major; move it down one semitone to E flat and the chord becomes minor.
The fifth - G supports the root and stays unchanged when C major becomes C minor.

The root does not have to be the lowest note. If E or G is in the bass, the same pitch classes can still form a C chord. Other notes matter in larger chords too. The seventh in G7, for example, helps create its pull toward C. Root, third and fifth are the starting structure, not a complete description of every chord.

Why is the middle note called a third?

Interactive

Interval numbers count letter names. From C to E you count C, D, E, so the distance is some kind of third. C to E flat uses the same three letter names and is also a third.

Semitones tell you the quality. C to E spans four semitones, making it a major third. C to E flat spans three, making it a minor third.

The fifth is named the same way. C, D, E, F, G gives five letter names, and C to G spans seven semitones. What Is an Interval? explains the complete counting method.

Count the letters

Press a letter to hear it. Then count a third: start on a letter, count that one as number one, and stop at three.

What changes C major into C minor?

C major contains C, E and G. Move E down one semitone to E flat and you get C minor: C, E flat, G.

The root and fifth remain fixed. This makes a back-to-back comparison useful: you can hear exactly what the third changes without also changing the chord's name or bass.

People often describe major as brighter and minor as darker. Those words describe a familiar contrast in Western music, but they are not fixed emotional instructions. A minor chord can sound calm, powerful or warm; tempo, register, rhythm and musical context still matter.

What are the four basic triads?

Keep C as the root and change the two measured distances:

C major: C-E-G | 4 and 7 semitones | major third and perfect fifth
C minor: C-E flat-G | 3 and 7 semitones | minor third and perfect fifth
C diminished: C-E flat-G flat | 3 and 6 semitones | minor third and diminished fifth
C augmented: C-E-G sharp | 4 and 8 semitones | major third and augmented fifth

Major and minor share the same perfect fifth and differ at the third. Diminished pulls the fifth one semitone inward. Augmented pushes it one semitone outward.

Play all four from the same root. Listening to one changing note at a time is more informative than memorizing four adjectives.

Does the root have to be the lowest note?

No. C-E-G, E-G-C and G-C-E contain the same three pitch classes, so all three can function as C major.

When C is lowest, the chord is in root position. When E is lowest, it is first inversion. When G is lowest, it is second inversion. The bass note changes the weight and voice leading, while the chord identity remains C major.

Repeating a note in another octave usually does not create a new chord either. C-E-G-C still contains the pitch classes C, E and G. This is called doubling, and it helps a chord fill a larger register.

Is an arpeggio still a chord?

A block chord sounds its notes at the same time. An arpeggio plays the chord tones one after another.

Play C, E and G separately and your ear can still connect them as C major when the pattern and context make that harmony clear. The chord describes the harmonic collection; the arpeggio describes how its notes are presented in time.

This is why a guitar picking pattern, piano accompaniment or bass line can imply a chord without striking every note at once.

How do you read a basic chord symbol?

The first letter names the root:

C means a C major triad
Cm means C minor
Cdim means C diminished
Caug or C+ means C augmented

With no quality mark, a plain letter normally means major in chord-symbol notation. A small m changes the third to minor.

Numbers need their own explanation. C7 and Cmaj7 add different kinds of seventh; C5 is a root-fifth power chord with no third; Csus4 replaces the third with a fourth. Read Chord Symbols before treating every number as simply one more note on top.

Build a chord, one note at a time

What you just learned

A chord is notes heard as one

Count keys to build it

Every note has a job

One note turns it minor

Four kinds of triad, in any key

Any order, same chord