A laptop, often called a notebook, is a portable personal computer with a clamshell form factor, suitable for mobile use. Although originally there was a distinction between laptops and notebooks, the former being bigger and heavier than the latter, in modern usage there is often no longer any difference. Laptops are commonly used in a variety of settings, such as at work, in education, and for personal multimedia.
A laptop combines the components and inputs of a desktop computer, including the display, speakers, a keyboard, and pointing devices (such as a touchpad or trackpad) into a single unit. Most modern-day laptops also have integrated webcams and built-in microphones. The device can be powered either from a rechargeable battery or by mains electricity from an AC adapter. Laptops are diverse devices and specialised kinds, such as rugged notebook or convertible computers, have been optimized for specific uses. The hardware specifications significantly vary between different types, makes, and models.
Portable computers, which later developed into modern laptops, were originally considered to be a small niche market, mostly for specialized field applications, such as in the military, for accountancy, or for sales representatives. As portable computers became closer to the modern laptop, they became widely used for a variety of purposes.
The terms laptop and notebook are used fairly interchangeably to describe a portable computer in English, although in some parts of the world one or the other may be preferred. There is some question as to the original etymology and specificity of either term—the term laptop appears to have been coined in the early 1980s to describe a mobile computer which can be used on one's lap, and to distinguish these devices from earlier, much heavier, portable computers (often called "luggables" in retrospect). The term "notebook" appears to have gained currency somewhat later as manufacturers started producing even smaller portable devices, further reducing their weight and size and incorporating a display roughly the size of A4 paper; these were marketed as notebooks to distinguish them from bulkier laptops. Regardless of the etymology, by the late 1990s, the terms were interchangeable.