Nut (fruit)

A nut is a fruit consisting of a hard or tough nutshell protecting a single seed. In botany, the use of the term nut implies that the shell does not open to release the seed (a property known as indehiscence).

Whereas most seeds come from fruit that naturally free themselves from their shell, this is not the case in true nuts (such as hazelnuts, chestnuts, and acorns), which have hard shell walls and originate from a compound ovary. Because nuts do not open of their own accord, they rely on external vectors of seed dispersal, such as consumption and excretion by herbivores.