Coconuts are not nuts.
They are fruits. More specifically: drupes
The name comes from the Spanish for skull, because the 3 indentations make it look like a face.
If you want to drink some coconut water you need to find the green ones - not the hairy ones.
Alert!!!
When you see a coconut in the wild: slowly walk around it. They are deadly. Coconuts attack and kill around 150 people per year. Sharks only five.
Save the shark! Kill a coconut instead.
Source
Coconut: Wikipedia
Drupe: Wikipedia
Death by coconut: Wikipedia