The B minor eleventh chord is a 6-note chord consisting of the notes B, D, F#, A, C# and E.
You can see these notes highlighted in the interactive piano chart below.
The chord itself is often abbreviated as Bm11.
Interactive piano diagram for the B minor eleventh chord
Chords that are a subset of Bm11. These contain less notes but all of them are included in Bm11.