subnotebook - technical definition

A laptop computer that weighs less than four pounds. In order to reduce weight, subnotebooks often eliminate built-in CD/DVD drives, relying on external units to be plugged in when needed. However, if optical discs are required on the road, an external drive in the same travel bag as the computer generally results in more overall weight than a built-in drive would have added in the first place.

The Mini Laptop/Netbook
Another category of small portables, the "mini laptop" made its debut in the 2007 time frame. It was quickly followed by the "netbook," a term coined by Intel for subnotebooks using its Atom processor. Weighing two to three pounds, mini laptops/netbooks have screens in the seven to nine inch range and no optical drives. For features of a portable computer, see laptop. See notebook and Ultra-Mobile PC.