The word rhinoceros usually triggers a mental image of a large, horned animal with tough skin. However, there are several synonyms for rhinoceros that may not be as well-known, such as unicorn, Indian rhinoceros, black rhinoceros, and white rhinoceros. Another synonym for rhinoceros is "pachyderm," which refers to any thick-skinned, heavily built mammal. The word "javan rhinoceros" specifically refers to the critically endangered species found in Indonesia, while "sumatran rhinoceros" is another species found in Southeast Asia. The term "Rhinocerotidae" refers to the family of rhinoceroses, which includes all species of the animal. While the physical appearance of the different types of rhinoceroses may vary, they all share the distinctive horn on their nose.