A nut
is a large single seed with a thick bony outside (preicarp).
Many
of the things we call nuts are really not true nuts.
Common
examples of true nuts are:
| acorns
(which humans do not eat becuase they are too bitter) |
 |
| chestnuts |  |
|
hazelnuts |
 |
When you eat a nut, you are eating the seeds of a plant. They contain the endosperm, of the stored food for the growing embryo. Normally, this food would be used as energy for a new plant to grow from the seed.