Source : Webster's Revised Unabridged Dictionary (1913)

Fluke \Fluke\ (fl[=u]k), n. [Cf. AS. fl[=o]c a kind of flatfish,
   Icel. fl[=o]ki a kind of halibut.]
   1. (Zo["o]l.) The European flounder. See {Flounder}. [Written
      also {fleuk}, {flook}, and {flowk}]. [1913 Webster]

   2. (Zo["o]l.) A parasitic trematode worm of several species,
      having a flat, lanceolate body and two suckers. Two
      species ({Fasciola hepatica} and {Distoma lanceolatum})
      are found in the livers of sheep, and produce the disease
      called rot. [1913 Webster]

Source : WordNet®

Fasciola hepatica
     n : flatworm parasitic in liver and bile ducts of domestic
         animals and humans [syn: {liver fluke}]