The D eleventh chord is a 5-note chord consisting of the notes D, A, C, E and G.
You can see these notes highlighted in the interactive piano chart below.
The chord itself is often abbreviated as D11.
Chords that are a superset of D11. The chords include more notes but always D, A, C, E and G.
Chords that are a subset of D11. These contain less notes but all of them are included in D11.
In case you prefer a non-interactive variant of the chord chart, we've embedded a PNG image below that shows the notes for the the D11 chord. Feel free to save or share the image as needed.