I don’t recall to have written ‘geo3d’ ever anywhere, but if someone else used it, I would assume that it’s simply short for ‘Geometry 3D’.
What has changed terminology wise is the introduction of “Immersive Screen Mode”, which sits between full VR and cinema mode immersion wise, for a slightly more detailed explanation please check the 17.3.0 release blog post.
The other change is that the old “Game Optimizer” in the config app is gone and now part of “Direct VR” as everything the old optimizer did now happens automatically – and a lot better – when a game starts. Since optimizer and memory scanner both adjust games to work better in VR, it makes more sense to simply use the same term for both, although technically they are completely different things.
So technically there is a “Direct VR Memory Scanner” and a “Direct VR Settings Optimizer”. From a user’s perspective however they both serve the same purpose, so both together are “Direct VR”.