pig-sized tailless South American amphibious rodent with partly webbed feet; largest living rodent
source: WordNet 3.0
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.