noun.
A large semiaquatic rodent (Hydrochoerus hydrochaeris) of tropical South America, having short limbs and a vestigial tail and often attaining lengths of more than 1.2 meters (4 feet).
The Century Dictionary and Cyclopedia
noun.
See capibara.
the GNU version of the Collaborative International Dictionary of English
noun.
A large South American rodent (Hydrochærus capybara) Living on the margins of lakes and rivers. It is the largest extant rodent, being about three feet long, and half that in height. It somewhat resembles the Guinea pig, to which it is related; -- called also cabiai and water hog.