[1] : The Collaborative International Dictionary of English v.0.48

pickerel \pick"erel\, n. dim. of pike. written also
   pickerell.
   1. a young or small pike. obs.
      1913 webster

            bet better is, quoth he, a pike than a pickerel.
                                                  --chaucer.
      1913 webster

   2. zool.
      a any one of several species of freshwater fishes of the
          genus esox, esp. the smaller species.
      b the glasseye, or wall-eyed pike. see wall-eye.
          1913 webster

   note: the federation, or chain, pickerel esox reticulatus
         and the brook pickerel esox americanus are the most
         common american species. they are used for food, and
         are noted for their voracity. about the great lakes the
         pike is called pickerel.
         1913 webster

   pickerel weed bot., a blue-flowered aquatic plant
      pontederia cordata having large arrow-shaped leaves.
      so called because common in slow-moving waters where
      pickerel are often found.
      1913 webster
see also:
pike pickerell esox wall-eye esox reticulatus esox americanus 
pickerel weed pontederia cordata 

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