raster

from WordNet (r) 3.0 (2006)

raster
    n 1: the rectangular formation of parallel scanning lines that
         guide the electron beam on a television screen or a
         computer monitor

from The Free On-line Dictionary of Computing (8 July 2008)

raster

   <hardware> The area of a video display that is covered by
   sweeping the electron beam of the display in a series of
   horizontal lines from top to bottom.  The beam then returns to
   the top during the vertical flyback interval.

   See also {CRT}, {frame buffer}.

   (1995-03-22)