What defines a sus chord?

A suspended chord, often abbreviated as "sus," is defined by the presence of a specific note that replaces the third in a major or minor chord. This means that the interval created by this alteration creates a feeling of 'suspension' because it has not yet resolved back to the traditional major or minor tonality. For instance, in a sus2 chord, the third of the chord is replaced by the second degree of the scale, while in a sus4 chord, it is replaced by the fourth degree.

The term "suspended" conveys that the chord is suspended over the tonic note (the root), creating a tension that typically seeks resolution, usually moving toward a more stable major or minor chord. This characteristic makes it distinct from other chord types since it should be understood not merely as "disassociated" from the root or tonality, but as a deliberate alteration that leads to a nuanced harmonic expectation.

While dissonance can often be a trait of sus chords due to the lack of the defining third, dissonance is not a defining feature in itself. Similarly, resolving onto a tonic is a common resolution for a suspended chord, but it does not define what a sus chord is. The intervals that create a sus chord