Texture EnVironment unit. It's basically the GC and Wii equivelant of Direct3D. Direct3D has the advantage of being well understood by the development community and the shaders can be programmed to operate as needed by the developer. The TEV is a fixed function pipeline in that all effects are locked in their application and few development studios have really taken the time to learn how capable the unit truly is. Some developers barely even touch it and don't use any graphical shaders at all. It's why you see games of tremedous graphical difference on GC and Wii between certain developers.
It also shows how ignorant many are of what the systems could do by how surprised the people who worked on RE5 were at what Darkside Chronicles could do. This despite RE4 showing what the GC could do.
I should add, just in case some claim this is part of "alienating" developers, that it's also developer willingness to use them, as they were certainly willing to work with the irregular programming of the PS2 and PS3. And those were at least as hard, and the latter even more expensive, but those somehow didn't alienate developers.
But back on topic it's also good that the 3DS is some kind of middle ground, as it means those working on it will be tricked into knowing how to use the Wii to some extent.
A flashy-first game is awesome when it comes out. A great-first game is awesome forever.
Plus, just for the hell of it: Kelly Brook at the 2008 BAFTAs