The hazelnut is the edible fruit of the hazel tree, mainly from the Corylus avellana species. These nuts, known as cobnuts or filberts, vary in shape; cobnuts are spherical to oval, while filberts are elongated.
Hazelnuts are typically 15–25 millimeters long and 10–15 millimeters in diameter, with a fibrous husk that encloses a smooth shell. The nuts fall from the husk about seven to eight months after pollination and can be eaten raw, roasted, or ground into a paste. They have a thin, dark brown skin that may be removed before cooking.
