Any one of a number of varieties of round hard–shelled nuts that grow in pairs or groups of three. In England, hazelnut refers to the wild or cultivated version, and cob and filbert are two varieties. In America, the wild nut is a hazel, and the cultivated a filbert. Unlike other oilier nuts, shelled hazelnuts keep well in an airtight container or in the freezer. Hazelnuts tend to be used in sweet dishes but are also used in savoury dishes, such as the Catalan salsa romesco.