Source : WordNet®

frame buffer
     n : (computer science) a buffer that stores the contents of an
         image pixel by pixel

Source : Free On-Line Dictionary of Computing

frame buffer
     
         Part of a video system in which an {image} is
        stored, {pixel} by pixel and which is used to refresh a
        {raster} image.  The term "{video memory}" suggests a fairly
        static display whereas a frame buffer holds one frame from a
        sequence of frames forming a moving image.
     
        Frame buffers are found in {frame grabbers} and {time base
        correction} systems, for example.
     
        (1997-10-03)