A laptop computer, or simply laptop (also notebook computer or notebook), is a small mobile (also portable) computer, which usually weighs 1 to 6 kg, depending on size, materials, and other factors.
Laptops usually run on a single main battery or from an external AC/DC adapter which can charge the battery while also supplying power to the computer itself.
In this category we probably will also list personal digital assistants (PDAs) as the gap between classical PC laptops, ultra mobile PCs (UMPCs) and PDAs is shrinking every day.