Mathematical Topics from 3D Graphics - 3D Math Primer for Graphics and Game Development - page 444

Figure 10.37. Data flow through the graphics pipeline.

10.10.1 Buffers

Rendering involves many buffers. In this context, a buffer is simply a
rectangular region of memory that stores some sort of data per pixel. The
most important buffers are the frame buffer and the depth buffer.
The frame buffer stores one color per pixel—it holds the rendered image.
The color for a single pixel may be stored in a variety of formats; the
variations are not significant for the current discussion. If we're rendering
a single image, the frame buffer may be in regular RAM, to be saved to
disk.