Yes that’s an interesting point, the “fragment” terminology can be confusing at first. But I think of fragments as something slightly different. “Fragment” means basically pixel or subpixel geometry, it’s output from the rasterizer. The fragment shader is what takes a fragment as input and then outputs the pixel or subpixel color. Fragments aren’t necessarily involved in GPU antialiasing, you can have subpixels in OpenGL without fragments, if you’re doing image processing without rasterizing. In any case, it’s a good thing that they picked a different word to define, and didn’t just call it “subpixel”, right?