Dictograph \Dic"to*graph\ (d[i^]k"t[-o]*gr[.a]f), n. [L. dictum
   a thing said + E. -graph.]
   A telephonic instrument for office or other similar use,
   having a sound-magnifying device enabling the ordinary
   mouthpiece to be dispensed with. Much use has been made of it
   for overhearing, or for recording, conversations for the
   purpose of obtaining evidence for use in litigation.
   [Webster 1913 Suppl.]

   Note: The makers of this instrument spell it dictograph.
         [Webster 1913 Suppl.]