A walnut is an edible seed of any tree of the genus Juglans (Family Juglandaceae); especially the Persian or English walnut; Juglans regia. Broken nutmeats of the eastern black walnut from the tree Juglans nigra are also commercially available in small quantities; as are foods prepared with butternut nutmeats from Juglans cinerea.

Walnuts are rounded; single-seeded stone fruits of the walnut tree. The walnut fruit is enclosed in a green; leathery; fleshy husk. This husk is inedible. After harvest; the removal of the husk reveals the wrinkly walnut shell; which is in two halves. This shell is hard and encloses the kernel; which is also made up of two halves separated by a partition. The seed kernels 鈥?commonly available as shelled walnuts 鈥?are enclosed in a brown seed coat which contains antioxidants. Pictures From History