nut, in botany, a dry one-seeded fruit which is indehiscent (i.e., does not split open along a definite seam at maturity). Among the true nuts are the acorn, chestnut, and hazelnut. Commonly the word nut is used for any seed or fruit having an edible kernel surrounded by a hard or brittle covering. Thus the peanut pod is actually a legume, the Brazil nut is a seed enclosed with others in a capsule, and the almond is part of a drupe, a type of fruit that includes olives and peaches. Others that are not botanically true nuts are the cashew, coconut, litchi, pistachio, and walnut. Most nuts have a high content of oil; in addition they may contain substantial amounts of protein, carbohydrates, minerals, and vitamins. Although nuts were originally harvested from wild trees, this century has seen the increasing cultivation of nut orchards—especially in warmer climates—for commercial production both for food and for byproducts.
See J. G. Woodroof, Tree Nuts (2 vol., 1967); R. A. Jaynes, ed., Handbook of North American Nut Trees (rev. ed. 1973).