Suspended 2nd
sus2
0 - 2 - 7Root + major 2nd + perfect 5th
About Suspended 2nd
A suspended second chord is a three-note chord in which the third is replaced by the second — in C that is C, D and G, written Csus2. Without a third it is neither major nor minor, and that missing information is the whole reason players use it: the chord fits over either one.
Notes and formula
The formula is 1 – 2 – 5, or 0 – 2 – 7 in semitones from the root. The third is not flattened or raised, it is absent, and the second stands where it would have been.
The chord is the same set of notes as a sus4 built on its fifth: C–D–G read from G is G–C–D, a Gsus4. Which name a chart uses depends on which note the bass is playing, and the sound of the two is genuinely different for that reason alone.
How to play it
On guitar Csus2 is x30013, and the shape is easier than the C major it comes from — the finger that frets the third simply lifts. Dsus2 at xx0230 and Asus2 at x02200 are the two that most players meet first, both a single lifted finger away from the open major chord.
On piano the chord is C–D–G. Voiced closely it sounds like a second and a fifth stacked; spread with the D above the G it turns into the open, ringing sound the chord is normally chosen for.
How it sounds
Suspended seconds sound open rather than unresolved, which distinguishes them from suspended fourths. A sus4 leans on the third below it and wants to fall; a sus2 sits on a fifth with a note added above the root, and nothing about that arrangement is uncomfortable.
The result is a chord that can be held indefinitely. Folk, ambient and post-rock guitar writing leans on it heavily, and so does anything played on a twelve-string, where the doubled open strings make the added second ring rather than crowd.
What it does in a progression
Its oldest use is decoration: play Csus2, then C, and the D falls to E as an ornament inside a single bar. That is where the name comes from, though modern practice suspends nothing and simply stays.
Its more common modern use is ambiguity. A song that alternates between a major and a minor version of the same chord can use the sus2 as a pivot, since it contradicts neither. Guitarists exploit this constantly when a capo or an open tuning makes the third awkward to reach.
Sus2, sus4 and add9
All three add a second degree to a triad, and they are not the same chord. Csus2 replaces the third with D. Csus4 replaces it with F. Cadd9 keeps the third and puts D an octave higher.
The audible difference is whether a third is present at all. Add9 is a major chord with colour; the two suspended chords have no quality, and that is why a chart marked sus can be played over a minor passage without correction.
Scales that contain it
Almost everything does. With no third, the chord is compatible with Ionian, Mixolydian, Dorian and Aeolian alike — every mode that keeps a natural second and a perfect fifth.
Only Phrygian and Locrian are excluded, the first because it lowers the second and the second because it lowers the fifth. That breadth is the practical value of the chord: it constrains the melody less than any other triad.
Frequently asked questions
What notes are in a Csus2 chord?
C, D and G. On guitar it is x30013 — an open C major with the third lifted and an added G on top.
Is a sus2 chord major or minor?
Neither. The third is the note that decides between major and minor, and a suspended second has none, which is why it can be played over either.
What is the difference between Csus2 and Cadd9?
Csus2 has no third: C, D, G. Cadd9 keeps it and raises the added note an octave: C, E, G, D. One is neutral, the other is a major chord with colour.