The Collaborative International Dictionary of English v.0.48:

Fisher \Fish"er\, n. [AS. fiscere.]
   1. One who fishes.
      [1913 Webster]

   2. (Zool.) A carnivorous animal of the Weasel family
      (Mustela Canadensis); the pekan; the "black cat."
      [1913 Webster]

WordNet (r) 3.0 (2006):

fisher
    n 1: someone whose occupation is catching fish [syn:
         fisherman, fisher]
    2: large dark brown North American arboreal carnivorous mammal
       [syn: fisher, pekan, fisher cat, black cat, Martes
       pennanti]