"Hazelnuts are not nuts"
Hazelnuts, coconut and almonds belong to the category with seeds inside fruits like peaches. "Nut" is the pit, as is the case of peach that has a soft inside but poisonous due to hydrocyanic acid content. Nut pulp is white-green and inedible. This breaks when the nuts ripen and begin to rot. No peanuts are not nuts themselves, but belong to the category legumes - like peas and beans.