\Cop"y*graph\, n.
A contrivance for producing manifold copies of a writing or
drawing.
Note: The writing or drawing is made with aniline ink on
      paper, and a reverse copy transfered by pressure to a
      slab of gelatin softened with glycerin. A large number
      of transcripts can be taken while the ink is fresh.
            Various names have been given to the process [the
            gelatin copying process], some of them acceptable
            and others absurd; hectograph, polygraph,
            copygraph, lithogram, etc.         --Knight.