Carya cordiformis, commonly known as the bitternut hickory, is a deciduous tree in the Juglandaceae (walnut) family. The genus name Carya derives from the ancient Greek karya (καρυα), meaning “nut tree.” The species epithet cordiformis means “heart-shaped” in Latin, referring to the form of the nut. The common name "bitternut" reflects the intensely bitter taste of the kernel.

Native to eastern and central North America, it is one of the most widely distributed hickories, found from Quebec and Ontario south to Florida and Texas. The tree produces nuts that resemble those of other hickories, but with an extremely bitter kernel, making them generally unsuitable for human consumption. Indigenous peoples occasionally used the nuts as a famine food or for oil extraction after leaching, but they were more valued as a wildlife food source for squirrels, birds, and other animals.

The wood of bitternut hickory is tough and elastic, historically prized for tool handles, furniture, and as an excellent firewood. Though not an important culinary nut like pecan (Carya illinoinensis) or shagbark hickory (Carya ovata), its presence is significant in barbecue as a smoking wood.