The term “laptop” can refer to a number of classes of small portable computers which are
Full-size Laptop: It is large enough to accommodate a “full-size” keyboard (a keyboard with the minimum QWERTY key layout, which is at least 13.5 keys across, plus some room on both ends for the case).
Netbook: A smaller, lighter, more portable laptop. It is usually cheaper than a full-size laptop, but has fewer features like less computing power and small keyboards. They have usually 10” screen size. They have no optical drive.
Tablet PC: They have touch screens and where the screen rotates to be used atop the keyboard, and “slate” form-factor machines which are usually touch-screen only and operated by a stylus. Most models have flip-over screens and the desktop display can be quickly switched from landscape to portrait mode. The case will also include extra buttons to the side of the screen for quick scrolling or navigation.
Rugged: Engineered to operate in tough conditions (mechanical shocks, extreme temperatures, wet and dusty environments).