We might just refer to it as Halo 5, as that's a lot quicker to write than 'the new Halo game'.
Whatever you want to call it, you can see its first full trailer below. In it we see Master Chief wearing a robe and looking thoughtful. At least, we reckon he's looking thoughtful behind that mask. Can you prove us wrong? Thought not.
The game is due out on Xbox One in 2014. It will apparently run in 60 frames per second at 1080p, as will many of the games revealed tonight.
Here's the trailer: