Laptops are personal computers designed for mobile use. They combine most of the typical components of a desktop computer, including a display, a keyboard, a pointing device (usually a touchpad or trackpad), a hard disk and speakers into a single unit. Many laptops also have an optical drive, a webcam and a wireless network adapter. A laptop is powered by mains electricity via an AC adapter, and can be used away from a power outlet using a rechargeable battery. Modern laptops can have a battery life of up to ten hours.
The earliest portable computers had monochrome CRT screens and were aimed at small niche markets, such as military users, accountants and sales representatives. As portable computers became smaller, lighter, cheaper, more powerful and as screens became larger and of better quality, laptops became very widely used for all sorts of purposes, by all sorts of people and now outsell desktop computers. Laptop screens generally range in size from 12 – 17 inches – anything smaller than this would be regarded as a netbook. Large laptops are sometimes referred to as desktop-replacement systems.
For further information, see the Wikipedia article on Laptops.