Walnut

A walnut is the edible seed of any tree in the genus Juglans, particularly the Persian or English walnut, Juglans regia; walnuts are technically accessory fruits, since the outer covering of the fruit is an involucre rather than part of the seed-bearing carpel, meaning it cannot be a true drupe but is instead a drupe-like nut. After the fruit fully ripens, its outer shell is discarded and the kernel inside is eaten; nuts of the related eastern black walnut and butternut are also edible but consumed less commonly.