What is a D2 chord?

A D2 chord, also known as a suspended two or sus2 chord, is a triad made up of the notes D, E and G. In sus2 chords, the middle note of the triad is a major second above the root instead of a minor or major third.

Because the major second interval between notes is dissonant, the suspended chords feel like they need to resolve upwards to minor or major chords. Sus2 chords are not often seen on their own; usually they occur near sus4 chords, delaying the even greater feeling of sus4 needing to resolve downward. Some famous songs with sus2 and sus4 chords are Michael Jackson's "Black or White" and John Lennon's "Happy Xmas (War Is Over)."