Source : Webster's Revised Unabridged Dictionary (1913)

Chub \Chub\, n. [This word seems to signify a large or thick
   fish. Cf. Sw. kubb a short and thick piece of wood, and perh.
   F. chabot chub.] (Zo["o]l.)
   A species to fresh-water fish of the {Cyprinid[ae]} or Carp
   family. The common European species is {Leuciscus cephalus};
   the cheven. In America the name is applied to various fishes
   of the same family, of the genera {Semotilus}, {Squalius},
   {Ceratichthys}, etc., and locally to several very different
   fishes, as the {tautog}, {black bass}, etc.

   {Chub mackerel} (Zo["o]l.), a species of mackerel ({Scomber
      colias}) in some years found in abundance on the Atlantic
      coast, but absent in others; -- called also {bull
      mackerel}, {thimble-eye}, and {big-eye mackerel}.

   {Chub sucker} (Zo["o]l.), a fresh-water fish of the United
      States ({Erimyzon sucetta}); -- called also {creekfish}.

Source : WordNet®

Leuciscus cephalus
     n : European freshwater game fish with a thick spindle-shaped
         body [syn: {chub}]