Mediant

In AP Music Theory, the mediant is the third scale degree of a major or minor scale, named because it sits midway between the tonic (scale degree 1) and the dominant (scale degree 5). In C major, the mediant is E.

Verified for the 2027 AP Music Theory examLast updated June 2026

What is the Mediant?

The mediant is the third scale degree in a diatonic scale. The name literally means "middle," because it splits the distance between the two most important pitches in tonal music, the tonic (scale degree 1) and the dominant (scale degree 5). In C major, that's E. In G major, it's B.

The mediant matters beyond just naming pitches. It's the note that tells your ear whether a key is major or minor, since the third above tonic is what changes between the two modes. Per the CED (PIT-1.E.1), every pitch in a scale functions relative to the tonic and gets a scale degree name, and the mediant is one of the eight you have to know cold: tonic, supertonic, mediant, subdominant, dominant, submediant, subtonic, and leading tone. A triad built on the mediant is the iii chord in major (III in minor), one of the least common diatonic chords, which is exactly why exam questions about it can feel sneaky.

Why the Mediant matters in AP Music Theory

The mediant lives in Unit 1 (Topic 1.4, Major Scales and Scale Degrees) under learning objectives 1.4.A and 1.4.B. You need to identify scale degrees by name and number in both performed and notated music, which means hearing or seeing a pitch and instantly knowing its job relative to the tonic. That skill is the foundation for everything later, especially Roman numeral analysis.

It also connects forward to Unit 5 (Topic 5.2, The vi Chord), mostly as a contrast. The submediant (scale degree 6) gets its own topic because the vi chord does real harmonic work as a tonic substitute and in deceptive progressions (PIT-2.J.1, PIT-2.J.2). The mediant is the term you confuse with it, so locking down the difference protects easy points across both units.

Keep studying AP Music Theory Unit 6

How the Mediant connects across the course

Submediant (Units 1 & 5)

The submediant is scale degree 6, and the naming logic mirrors the mediant's. The mediant sits a third above tonic, while the submediant sits a third below it ("sub" means under). Mixing these two up is the single most common scale-degree error on the exam.

Tonic (Unit 1)

Every scale degree name describes a relationship to the tonic, and the mediant is no exception. Its third above the tonic is what defines the quality of the tonic triad, so the mediant is literally the note that makes a key sound major or minor.

Dominant (Unit 1)

The mediant gets its name from being the midpoint between tonic and dominant. Picture scale degrees 1, 3, and 5 stacked as a triad. The mediant is the middle note of that tonic chord, which is why it feels stable but not as grounded as the tonic itself.

Circle of fifths (Unit 1)

Once you can name the mediant in any key, the circle of fifths becomes a quick-check tool. Move to any key on the circle and the mediant is always a major third above tonic in major keys, so you can spot-check answers fast on scale-degree MCQs.

Is the Mediant on the AP Music Theory exam?

Scale degree identification shows up in multiple-choice questions in both written and aural formats. You'll hear or see a melody and need to label a specific pitch as the mediant, or you'll be given a key and asked which note is scale degree 3. Speed matters here, so practice naming the mediant of all 15 major keys until it's automatic.

Watch for distractor answers that swap mediant and submediant. Practice questions also love to test the family of related ideas, like which scale degree creates tension that resolves to tonic (that's the leading tone, not the mediant) and how the submediant chord behaves in deceptive progressions. Knowing exactly what the mediant is keeps you from falling for those near-miss options. No released FRQ centers on the mediant by name, but scale-degree fluency feeds directly into the Roman numeral analysis and harmonization FRQs.

The Mediant vs Submediant

The mediant is scale degree 3; the submediant is scale degree 6. The trick is the prefix. "Sub" means below, so the submediant is a third below the tonic, mirroring how the mediant is a third above it. In C major, the mediant is E and the submediant is A. On the exam, the submediant does more harmonic heavy lifting (the vi chord in deceptive progressions), while the mediant is mostly tested as a scale-degree label.

Key things to remember about the Mediant

  • The mediant is the third scale degree, named because it sits midway between the tonic and the dominant.

  • In C major the mediant is E; to find it in any key, go a third above the tonic.

  • The mediant determines whether a key sounds major or minor, since scale degree 3 is the note that changes between the two modes.

  • Don't confuse the mediant (scale degree 3) with the submediant (scale degree 6), which is a third below the tonic and powers the vi chord in deceptive progressions.

  • The triad built on the mediant is iii in major keys and III in minor keys, one of the rarest diatonic chords in common-practice harmony.

  • CED objective 1.4.B requires identifying scale degree names like mediant in both performed (aural) and notated music.

Frequently asked questions about the Mediant

What is the mediant in music theory?

The mediant is the third scale degree of a major or minor scale, located a third above the tonic. In C major it's E, and in A minor it's C. It gets its name from sitting in the middle between the tonic and the dominant.

Is the mediant the same as the submediant?

No. The mediant is scale degree 3 and the submediant is scale degree 6. The submediant is a third below the tonic, while the mediant is a third above it, which is exactly what the "sub" prefix signals.

Why is it called the mediant?

"Mediant" comes from the Latin for "middle." Scale degree 3 sits exactly halfway between the tonic (degree 1) and the dominant (degree 5), the two anchor pitches of tonal music.

Does the mediant create tension that resolves to the tonic?

Not really. That description fits the leading tone (scale degree 7), which pulls strongly up to tonic. The mediant is part of the tonic triad itself, so it sounds relatively stable. AP multiple-choice questions use this exact mix-up as a distractor.

What chord is built on the mediant?

The mediant triad is iii in major keys (a minor triad) and III in minor keys (a major triad). It's one of the least common diatonic chords in common-practice harmony, unlike the submediant's vi chord, which gets its own CED topic for its role in deceptive progressions.