The A minor eleventh chord is a 6-note chord consisting of the notes A, C, E, G, B and D.
You can see these notes highlighted in the interactive piano chart below.
The chord itself is often abbreviated as Am11.
Chords that are a subset of Am11. These contain less notes but all of them are included in Am11.
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 Am11 chord. Feel free to save or share the image as needed.