pig-nut, or earth-nut, in botany: A genus of the digynia order, belonging to the pentandra clas of plants; and in the natural method ranking under the 45th order, Umbellatae. The corolla is uniform, the umbel thick, and the fruit ovate. There is but one species, the bulbocastanum, with a globular root. This grows naturally in moist pastures in many parts of Britain. It hath a tuberous solid root, which lies deep in the ground. The leaves are finely cut, and lie near the ground. The stalk rises a foot and an half high; is round, channelled, and solid; the lower part being naked; but above, where it branches out, there is one leaf placed below every branch. The flowers are white, and shaped like those of other umbelliferous plants; the seeds are small, oblong, and when ripe are channelled. The roots of this sort are frequently dug up, and by some people eaten raw. They have much resemblance in taste to a chestnut, whence the plant obtains the name of bulbocastanum.