The E lydian dominant seventh chord is a 5-note chord consisting of the notes E, G#, B, D and A#.
You can see these notes highlighted in the interactive piano chart below.
The chord itself is often abbreviated as E7#11.
Interactive piano diagram for the E lydian dominant seventh chord
Chords that are a subset of E7#11. These contain less notes but all of them are included in E7#11.