Source : Webster's Revised Unabridged Dictionary (1913)

Polygraphy \Po*lyg"ra*phy\, n. [Gr. ?; poly`s much + gra`fein to
   write: cf. F. polygraphie.]
   1. Much writing; writing of many books. [Obs.] --Fuller.

   2. The art of writing in various ciphers, and of deciphering
      the same. [R.]

   3. The art or practice of using a polygraph.