Trees in the genus Carya (from Ancient Greek "nut") are commonly known as hickory, derived from the Powhatan language of Virginia. The genus includes 17–19 species of deciduous trees with pinnately compound leaves and big nuts. Between five and six species are native to China, Indochina, and India (Assam Province), 11 to 12 are from the United States, two to four are from Canada and four are found in Mexico.
Another Asian species, beaked hickory, previously listed as Carya sinensis, is now treated in a separate genus, Annamocarya, as Annamocarya sinensis.
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 (0.79–2.0 in) long and 1.5–3 cm (0.59–1.2 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 C. illinoinensis; it is divided into two halves, which split apart when the seed germinates.