Peanut

a legume and not a nut (Arachis hypogea), it is the plant's nut-like seed that grows underground; the hard nut has a papery brown skin and is encased in a thin, netted tan pod and is used for snacking and for making peanut butter and oil; also known as a groundnut; earthnut, goober (from the African work nguba) and goober pea.