A notebook computer or notebook is, historically, a laptop whose length and width approximate that of letter paper.
The NEC UltraLite defined the modern notebook on its release in 1988.
The Epson HX-20 from 1982 was the first portable computer to be called a "notebook".
The Sharp PC-4641, a laptop released in the same month as the UltraLite. Larger laptops continued to be marketed alongside notebooks for several years.
Toshiba's DynaBook J-3100SS was cited by the company as the "first notebook PC"