Source : Webster's Revised Unabridged Dictionary (1913)

Cavy \Ca"vy\, n.; pl. {Cavies}. [NL. cavia, fr. Brazilian
   cabiai: cf. F. cabiai.] (Zo["o]l.)
   A rodent of the genera {Cavia} and {Dolichotis}, as the
   guinea pig ({Cavia cobaya}). Cavies are natives of South
   America.

   {Water cavy} (Zo["o]l.), The capybara.

Source : WordNet®

cavy
     n : short-tailed rough-haired South American rodent