1. Any of the nearly tailless rodents of the family Caviidae of South America, including the capybara, coypu, agouti; and the best known, the Guinea pig: "Sam got a cavy from his parents on his birthday, and he also received a book about them, so he could learn that they are friendly animals, which have rough hair, little ears, short legs, and are gray or brown in color."

"The cavies feed on leaves, grass, and other vegetation."

2. Etymology: from New Latin Cavia; possibly from Galibi cabiai.