Hickory is a common name for trees composing the genus Carya, which includes around 18 species. Five or six species are native to China, Indochina, and India (Assam), as many as twelve are native to the United States, four are found in Mexico, and two to four are native to Canada. A number of hickory species are used for their edible nuts, lumber or other wood and woodcraft products.
Hickory
Roasted Carya cathayensis (Chinese hickory)
Nuts of Carya texana (black hickory)
Foliage of Carya cordiformis (bitternut hickory)
A nut is a fruit consisting of a hard or tough nutshell protecting a kernel which is usually edible. In general usage and in a culinary sense, a wide variety of dry seeds are called nuts, but in a botanical context "nut" implies that the shell does not open to release the seed (indehiscent).
Chestnuts are both botanical and culinary nuts.
Nuts being sold in a market
Raw mixed nuts, sold as a snack food
Image: Almonds in shell, shell cracked open, shelled, blanched