Hickory is a type of tree, comprising the genus Carya (Ancient Greek meaning "nut"). The genus includes 17 to 19 species. Five or six species are native to China, Indochina, and India (State of Assam), as many as 12 are native to the United States, four are found in Mexico, and two to four are from Canada.
Hickories are deciduous trees with pinnately compound leaves and large nuts. Hickory flowers are small, yellow-green catkins produced in spring. They are wind-pollinated and self-incompatible. The fruit is a globose or oval nut, 2–5 cm (0.79–1.97 in) long and 1.5–3 cm (0.59–1.18 in) diameter, enclosed in a four-valved husk, which splits open at maturity. The nut shell is thick and bony in most species, and thin in a few, notably the pecan (C. illinoinensis); it is divided into two halves, which split apart when the seed germinates.
Hickory wood is very hard, stiff, dense and shock resistant. There are woods that are stronger than hickory and woods that are harder, but the combination of strength, toughness, hardness and stiffness found in hickory wood is not found in any other commercial wood. It is used for tool handles.