The groundnut, or root of the Arachis; a small round bulb or knob, like a nut. This root or bulb is formed from the germen, which becomes a pod and is thrust into the ground by a natural motion of the stalk. It is properly the fruit of the plant, and differs from other fruit only in the circumstance of ripening in the earth.

The pignut, or bunium; a globular root, somewhat resembling in taste a chestnut, whence it is called bulbocastanum.