OpenGL Programming Guide: The Official Guide to Learning OpenGL, Version 4.3, Eighth Edition

Rasterization

Immediately after clipping, the updated primitives are sent to the rasterizer for fragment generation. Consider a fragment a “candidate pixel”, in that pixels have a home in the framebuffer, while a fragment still can be rejected and never update its associated pixel location. Processing of fragments occurs in the next two stages, fragment shading and per-fragment operations.