What is the difference between a Laptop, a Notebook, & a Netbook?

Laptops are your usual stuff, the 15.6 " screens and bigger models and offer some kind of power. In the begging we had only the laptop name but then...
Notebooks are the same size but not that powerful, more suited for internet, office, simple stuff.
Netbooks are those little horrible stuff that i hate more than Nicki Minaj. Just some miserable pieces of expensive, ugly, far to small of sh*t....but similar in power with notebooks but, you know, smaller for...being small?