Crocodylus is a genus of large aquatic reptiles that are commonly known as crocodiles. Some synonyms for the word crocodylus include crocodylidae, crocodilian, caiman, gharial, and alligator. Crocodylidae is a family of crocodilians that includes the true crocodiles. Crocodilian is a term that refers to any member of the Crocodilia order, including the alligators, crocodiles, caimans, and gharials. Caiman is a species of crocodilian that is similar in appearance to alligators. Gharial is a type of crocodilian that has a narrow snout and is native to India. Alligator is a type of large crocodilian that is characterized by a broad snout and is native to the Americas.