Source : Webster's Revised Unabridged Dictionary (1913)

Plater \Plat"er\, n. (Horse Racing)
   A horse that runs chiefly in plate, esp. selling-plate,
   races; hence, an inferior race horse.

Plater \Plat"er\, n.
   One who plates or coats articles with gold or silver; as, a
   silver plater.

   2. A machine for calendering paper.

Source : WordNet®

plater
     n : a skilled worker who coats articles with a film of metal
         (usually silver or gold)