The Jargon File (version 4.4.7, 29 Dec 2003):

blitter
 /blit'r/, n.

    [common] A special-purpose chip or hardware system built to perform blit
    operations, esp. used for fast implementation of bit-mapped graphics. The
    Commodore Amiga and a few other micros have these, but since 1990 the trend
    has been away from them (however, see cycle of reincarnation). Syn. 
    raster blaster.


The Free On-line Dictionary of Computing (30 December 2018):

blitter

    /blit'r/ (Or "raster blaster").  A
   special-purpose integrated circuit or hardware system built
   to perform blit (or "bit bang") operations, especially
   used for fast implementation of bit-mapped graphics.

   The Commodore Amiga and a few other microcomputers have
   these, but in 1991 the trend is away from them (however, see
   cycle of reincarnation).

   [Jargon File]

   (1996-04-30)