Distinguishing between nuts and seeds is not very easy. Classification varies according to the academic or colloquial usage of the words.
A seed is the new plant in the embryonic state. It contains a miniature undeveloped plant. Some seeds carry a store of food to help with early development after germination. Seeds are covered with a protective coat called the testa.
A nut is a woody fruit enclosed in a thick husk. They are hard shelled fruit. Being a fruit, the nut contains the seed.
Seeds are economically significant as they are the source of a large variety of foods. In addition other important things are obtained from seeds. Cereals like rice, wheat, maize and millets are edible seeds. Cooking oil is made from the seeds of mustard oil, sunflower, safflower, flax, and rapeseed and soya bean. Essential oils are obtained from juniper seeds, stimulants from coffee and poppy seeds, and spices like pepper, nutmeg, coriander, cumin, caraway and dill are obtained from seeds. Wax and dyes too come from seeds.
Nuts like walnuts, chestnuts, acorns and hazelnuts are an important source of nutrients for man. They provide proteins, vitamins, minerals and fats. Nuts are especially important in vegetarian diets that lack protein.
Peanuts and groundnuts are commonly referred to as nuts, but they are actually legumes.
Cashew nuts are seeds, unlike walnut and hazelnut. Almonds, usually classed as a nut, are actually edible seeds. Pistachio nuts too are embryonic, making them seeds.
A seed is a fertilized ovule. It bears a scar called the hilum, marking the spot where the ovule was attached to the ovary. Seeds also have a microphyle, a microscopic hole to let water in before germination.
In culinary terms nut and seed and often used interchangeably. Garnish with nuts, suggests that the chef should use cashew nuts, almonds, walnuts, or pistachio nuts. None of these are nuts. The walnut actually falls into the botanical classification of drupe. The rest are seeds.
Botany defines a nut as a dried fruit containing one -rarely two- seeds. True nuts are pecan, sweet chestnut, acorn, hazel and alder.
Nuts that we use in the kitchen have a hard outer covering that does not split open on its own. The shell has to be cracked with a nutcracker or teeth if you have a strong enough set.
In conclusion we can say that some nuts are fruit, and some are seeds.
The coconut is a fruit, when the outer part is removed we get the edible seed.
The botanical differences do not have much impact on the use of nuts in our diets.
We will continue to refer to those fruit or seed or drupe, as nuts.
They have always been nuts to us and will always be – the coconut, cashew nut, pistachio nut, almonds, macadamia, hazelnuts, pine nuts, walnuts, peanut, pecan and all those delicious, nutrients that enhance the flavour of our food or serve as a healthy any time snack.