The peanut, or Groundnut (Arachis hypogaea), is a species in the legume family Fabaceae native to South America, Mexico and Central America.
It is an annual herbaceous plant growing to 30 to 50 cm (1 to 1½ ft) tall.
The leaves are opposite, pinnate with four leaflets (two opposite pairs; no terminal leaflet), each leaflet 1 to 7 cm (⅜ to 2¾ in) long and 1 to 3 cm (⅜ to 1 inch) broad.
The flowers are a typical peaflower in shape, 2 to 4 cm (¾ to 1½ in) across, yellow with reddish veining.
After pollination, the fruit develops into a legume 3 to 7 cm (1 to 2 in) long containing 1 to 4 seeds, which forces its way underground to mature.
The plant's name combines the morphemes pea and nut, causing some confusion as to the nature of the fruit.
Although a nut in the culinary sense, in the botanical sense the fruit of the peanut plant is a woody, indehiscent legume and not a nut.
The word pea describes the edible seeds of many other legumes in the Fabaceae family, and in that sense, a peanut is a kind of pea.