Peanuts are actually a legume, not a nut. They grow underground and, like soybeans, play a big part in crop rotation. Peanuts are a good source of vitamin E, niacin and folate. Roasted, they are a delicious staple at American baseball games! Nearly everyone loves peanut butter and all the cool stuff you can make with it. Tree nuts are a completely different thing. You can be allergic to peanuts but not tree nuts and vice versa.

More Info: en.wikipedia.org