The D9 sus 4 chord (D9 suspended 4, or C/D) contains the notes D, G, A, C and E. It can be thought of as a D9 chord with a 4th (instead of a 3rd) or a C chord with a D in the bass.
10 Ways To Play The D9 Sus 4 chord
If you’ve come to this page just to view some chord diagrams for D9 Sus 4 (C/D), here they are.
