- any of several large, thick-skinned, perissodactyl mammals of the family Rhinocerotidae, of Africa and India, having one or two upright horns on the snout: all rhinoceroses are endangered.
- unicorn (def. 4).
- any of several perissodactyl mammals constituting the family Rhinocerotidae of SE Asia and Africa and having either one horn on the nose, like the Indian rhinoceros (Rhinoceros unicornis), or two horns, like the African white rhinoceros (Diceros simus) They have a very thick skin, massive body, and three digits on each foot