A hazelnut is also known as a cob nut or filbert nut according to its species.

A cob is roughly spherical to oval, about 15–25 mm long and 10–15 mm in diameter, with an outer fibrous husk surrounding a smooth shell.

A filbert is more elongated, being about twice as long as it is round. The nut falls out of the husk when ripe, about 7–8 months after pollination.

The seed can be eaten raw or roasted, or be ground into a paste.

Hazelnuts are also used for livestock feed. The seed has a thin, dark brown skin which is removed before cooking.

Hazelnuts are produced in Turkey, Italy, and parts of U.S.A. Turkey is the largest producer of hazelnuts in the world.

Hazelnuts are extensively used in confectionery. Hazelnut oil is a strongly flavored cooking oil.
Hazelnuts are rich in protein, unsaturated fat, thiamine and vitamin B6.

Hazelnuts have a significant place among the types of dried nuts in terms of nutrition and health.

The nutritional and sensory properties of hazelnuts make them a unique and ideal material for food products.

Hazelnuts are a good source of energy with their 60.5% fat content.