Cop·y·graph n. A contrivance for producing manifold copies of a writing or drawing; -- made obsolete by later developments in copying technology; see xerography.
 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.

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