The A flat minor eleventh chord is a 6-note chord consisting of the notes Ab, Cb, Eb, Gb, Bb and Db.
You can see these notes highlighted in the interactive piano chart below.
The chord itself is often abbreviated as Abm11.
Interactive piano diagram for the A flat minor eleventh chord
Chords that are a subset of Abm11. These contain less notes but all of them are included in Abm11.