Notebook vs Laptop

Got the question the other day: What's the difference between a notebook and a laptop?

I thought they were both the same, but I thought I'd double check on the Internet.

Seems as though there are many answers to this one, although there seems to be some concensus on the differences.

A Notebook is generally ultralight, with no internal floppy, DVD or CD system, and a screen no larger than 14".

A Laptop is heavier, with a screen larger than 14", an internal DVD drive and a full featured keyboard as well as integrated wireless capabilities. And a laptop is upgradeable.

But, of course, the main difference is that a laptop is designed to sit on your lap, hence the name.

To me, they are all portable and that's the most important thing.