Nut (fruit) usage of the term is less restrictive, and many nuts (in the culinary sense), such as almonds, pecans, pistachios, walnuts, and Brazil nuts, are not nuts in a botanical sense. Common usage of the term often refers to any hard-walled, edible kernel as a nut. A nut in botany is a simple dry fruit in which the ovary wall becomes increasingly hard as it matures, and where the seed remains unattached or free within the ovary wall. Most nuts come from the pistils with "inferior" ovaries (see flower) and all are "indehiscent" (not opening at maturity). True nuts are produced,
Nut (hardware) nylon inserts (nyloc nut), or slightly oval-shaped threads. Square nuts, as well as bolt heads, were the first shape made and used to be the most common largely because they were much easier to manufacture, especially by hand. While rare today due to the reasons stated below for the preference of hexagonal nuts, they are occasionally used in some situations when a maximum amount of torque and grip is needed for a given size: the greater length of each side allows a spanner to be applied with a larger surface area and more leverage at the nut. The most common