To clarify: The North American white-tailed deer is to be distinguished from the red deer, which looks like a smaller wapiti. The wapiti is named for its white tail; in the Shawnee language waapiti means white tail. When Europeans arrived in North America, they thought the wapiti looked like a moose, so they called it elk, because elk was their word for moose. Then, when they saw some actual moose, they had already used up their word for it (elk) and so adopted the Narragansett word for moose, which is moose. Back in Europe, a moose is still an elk.