* Bison: The American bison is the large, shaggy mammal commonly called a "buffalo" in North America. They are a type of bovid, related to cattle, and were once abundant across the continent. Today, they are still an important part of the ecosystem and are considered a symbol of the American West.
* Water buffalo: The water buffalo is a different species, native to Asia and Africa. It is also a bovid but is more closely related to the domestic cow. Water buffalo are primarily found in warmer climates and are often used for their milk and meat.
So, when someone says "American buffalo", they are usually talking about the American bison. However, it's important to be mindful of the context to avoid confusion.