Source : Webster's Revised Unabridged Dictionary (1913)

Waterfowl \Wa"ter*fowl`\, n.
   Any bird that frequents the water, or lives about rivers,
   lakes, etc., or on or near the sea; an aquatic fowl; -- used
   also collectively.

   Note: Of aquatic fowls, some are waders, or furnished with
         long legs; others are swimmers, or furnished with
         webbed feet.

Source : WordNet®

waterfowl
     n : freshwater aquatic bird [syn: {water bird}, {waterbird}]