I'm pretty sure coconuts are nuts, but I've stopped calling them coconuts since they were referred to as 'bear eggs' on Shooting Stars. It's good to speak about bear eggs with a bunch of pissed 16 year olds in a snooker club.
I looked it up (wiki) because it was bugging me and apparently coconuts aren't nuts but are classed as a dried fruit. I had a coconut yesterday incidentally and it was possibly the easiest coconut I have ever cracked. Good hammer blow, shell split and peeled off the coconut.
In a vain attempt to keep the nut thread going...what's the hardest nut to crack? Brazil nuts get my vote I think.