French-Canadian colonists called it Bison d' Amerique.The French voyageurs (voy-uh-ZHOORS) called it boeuf — the source of the English word beef. Later in the 17th century, French explorers expanded it to bufflo, and later buffelo.1
The noun buffalo apparently began to be applied to the American species in 1635, and has remained the common vernacular name ever since.2 Bison is more recent, dating in print from 1774. The journalists of the Corps of Discovery used buffalo exclusively — in various spellings, of course.
At present, bison and buffalo are used interchangeably. The latter name is actually incorrect; it properly denotes the water buffalo of Asia and the Cape buffalo of Africa, which belong to different genera. The name for our national icon which is accepted as correct today is American bison (with a soft s in the U.S., but pronounced bizon in Canada). The scientific name for the American bison has had an equally confusing history.
The Swedish naturalist Carolus Linnaeus (1707-1778), had already listed it as Bison americanus, but that was merely the beginning. Today, the National Audubon Society's Field Guide to North American Mammals lists it as Bos bison. Bos, the generic name, is Latin for cow; bison denotes the species. Bos bison belong to the family Bovidae, consisting of large hoofed animals having hollow horns, which includes domestic cattle (Bos taurus), sheep, and goats. Bison are so closely related to Bos taurus that they can readily interbreed.