PVP Rewards - Nether?

[Stigg]

I was glancing through the official site looking at the PVP rewards. I know the symbols for AV, WSG, and AB marks, but what is Nether? I don't know if that is the name for it, but it was the name of the pic when I tried to save it.

Here it is:
http://www.worldofwarcraft.com/shared/wow-com/images/basics/factions/nether.gif

I'm assuming it is arena, but it could be the other 3 combined...but I just wanted to make sure before I dove into the BG's!

[Spennce]

Eye of the Storm, new BG with the xpac.

[Stigg]

Thank you Spennce!