Is a sweet chestnut a nut, a fruit, or something else?

Answer

What is popularly called ‘fruit’, ‘nuts’ and ‘fruits’ can sometimes differ from the botanical meaning. According to the botanical definition, a nut is a fruit where the ‘flesh’ becomes hard and woody and the seed is loose inside. Examples include hazelnuts, beechnuts, acorns and, indeed, sweet chestnuts. The husk of the sweet chestnut, like the shells of hazelnuts, acorns and beechnuts, is formed by other parts of the plant and does not belong to the actual fruit.

Many ‘notes’ as we call them in everyday language are not nuts according to the botanical meaning, eg. wild chestnuts (the husk is the fruit, the chestnut is the seed), walnuts (the shell is part of the fruit), cashew nuts (seeds), and so on.

Regards

Francis