What we call portable computers can easily refer to laptops or notebooks. It is often not quite clear what differentiates these two. The original differentiating factor which is the size and bulk is no longer applicable as laptops become smaller and lighter with the introduction of new models. It is not an exaggeration to say that it can be very difficult to know the difference merely by physical appearance.
The bigger size of early laptops was due to the reason that it was designed to be a portable desktop in relation to power and amount of hardware. The notebook, on the other hand, has been designed ever since for maximum mobility from its design to its contents. With everything stripped down to the basics, users had to contend with smaller displays, less power and hardware, and less engaging graphics and sound.
Newer advances in technology have made it possible to pack in more power and features into a smaller package thereby totally obliterating the physical difference between a laptop and a notebook. Portable computer owners never had it so good as now as power and mobility finally merged. This is only expected to get better as future improvements set in.
Laptops and notebooks perform basically the same functions but since there is still a difference in its contents, each can perform better depending on the task to be performed. Notebook use is typically limited to quick tasks such as checking of email and is still the probable choice of owners whose everyday activity requires extreme mobility. Laptops still have larger capabilities and can accommodate other tasks such as longer work sessions or watching videos. Notebook typically cannot accommodate more complex systems found in laptops.
Manufacturers tend to shy away from naming their products as laptops because of the preconceived idea of bulk. Most have opted for alternate branding that seems to attach their products to notebooks. This is a sure signal therefore that the time will come that notebooks and laptops will completely be the same inside and out. This would of course necessitate another name for the resulting product.