Source : Webster's Revised Unabridged Dictionary (1913)

Steelhead \Steel"head`\, n.
   1. (Zo["o]l.) A North Pacific salmon ({Salmo Gairdneri})
      found from Northern California to Siberia; -- called also
      {hardhead}, and {preesil}.

   2. (Zo["o]l.) The ruddy duck.