Real Dictionary

peanut
Peanuts are small nuts that grow under the ground. Peanuts are often eaten as a snack, especially roasted and salted.

peanut in American English
a spreading, annual vine (Arachis hypogaea) of the pea family, with yellow flowers and brittle pods ripening underground and containing one to three edible seeds
noun: the pod or the enclosed edible seed of the plant, Arachis hypogaea, of the legume family: the pod is forced underground in growing, where it ripens

peanut in British English
noun: a leguminous plant, Arachis hypogaea, of tropical America: widely cultivated for its edible seeds. The seed pods are forced underground where they ripen