A coconut, when it is removed from a coconut palm tree , is a fruit and a one seeded fruit at that.
Botanically speaking it is classified as DRUPE . The greenish or yellowish skin is the outer skin of the fruit or epicarp ( epi = outer; carp = fruit); the middle fibrous part is the mesocarp ( meso = middle). This mesocarp , being fibrous, is the commercial source of coir fiber, many tropical countries are famous for it. The inner most part of the fruit is very hard, stony and shell like; it is the endocarp (endo = inner or inner most). It is because of this hard endocarp the fruit is called NUT.
The fruit part ends with the endocarp and the seed part begins.
The edible part of the fruit, which well protected by the endocarp, is the SEED.
When young and immature this part is mostly liquid, and very delicious liquid at that, and commonly called coconut water.
As the fruit, or the seed if you like, matures the liquid part solidifies and turns in to ‘ copra’ in native language. This solid copra has its own skin which is invariably Cadbury chocolate brown in colour. That is exactly the skin or the wall of the seed and botanically Testa, that is wall of a seed.
The seed encloses a small embryo located just below one of the three distinct dark spots on the shell.
It invisible and can be noticed only when the seed begins to germinate.
The solidified and dry copra is the source of coconut oil of commerce. Botanically it is called endosperm.
IN A NUTSHELL, A COCONUT AS IT FALLS TO THE GROUND IS A FRUIT.
THE FRUIT PART ENDS WITH THE HARD SHELL OR ENDOCARP.
THE SEED PART BEGINS WITH THE CHOCOLATE BROWN TESTA AROUND THE OILY ENDOPERM.
Foot Note: - 1) The fibrous mesocarp is also known as the husk. Removal of this husk from the nut is called Dehusking or simply husking of nut. The coir obtained from the husk has a number of commercial uses. The chief among them is rope and mats.
2) Completely dry endosperm easily separates from the hard shell and has a spherical shape and the size of a cricket ball. This is the real seed The dark brown testa is easily visible in such a case.
The dry endosperm yields plenty of oil which edible, and has a score of cosmetic applications. The solid residue that remains behind after oil extraction is very rich source of proteins.
3) The hard shell is a good source of fuel and burns fiercely. In fact no part of the tree is wasted. It is one of the Nature’s bounty to man kind.