Difference between Laptop and Notebook computer

Notebooks and Laptops are portable computers but there is a minor difference between laptops and notebooks.

Laptop: A portable computer small enough to use on one's lap.

Notebook: A light, portable computer that is generally thinner than a laptop.

Even according to Webopedia, laptop computers are more frequently called notebook computers, though technically laptops are somewhat smaller in size than notebooks.

Source: Notebook Computer | Laptop Computer