The Collaborative International Dictionary of English v.0.48:

Converter \Con*vert"er\, n.
   1. One who converts; one who makes converts.
      [1913 Webster]

   2. (Steel Manuf.) A retort, used in the Bessemer process, in
      which molten cast iron is decarburized and converted into
      steel by a blast of air forced through the liquid metal.
      [1913 Webster]

WordNet (r) 3.0 (2006):

converter
    n 1: a device for changing one substance or form or state into
         another [syn: converter, convertor]