Performance measure: depending on the context it is used in, it shows the number of pixel or texels used in a second for the rendering.
The speed at which your graphics card can render pixels–usually measured in millions of pixels per second (Megapixels/sec). GPUs with higher fill rates can display higher resolutions and more colors at higher frame rates than other chips with lower fill rates. NVIDIA GPUs have the highest fill rates of all GPU available on the market. See Frames Per Second.
The number of pixels that a video card is capable of producing in a second. Current video cards are capable of in excess of 400 millions pixels/sec fill rates.
The speed at which the hardware can render pixels-usually measured in millions of pixels per second (Megapixels/sec).
The speed at which a 3D accelerator can texture-map polygons.
The number of pixels that can be rendered on screen per second. (Pixels, or "picture elements," are literally the dots that appear on your computer display.) A 3D accelerator card with extremely high pixel fill rates is a must for serious gaming action. More...
Time required to fill a gallon container, used to measure flow rate. A fill rate in excess of 35 seconds for a gallon container is considered "low water flow".