The art or practice of steel engraving; especially,
   the process, invented by Perkins, of multiplying facsimiles of an
   engraved steel plate by first rolling over it, when hardened, a soft
   steel cylinder, and then rolling the cylinder, when hardened, over a
   soft steel plate, which thus becomes a facsimile of the original. The
   process has been superseded by electrotypy.