A notebook is a PC that is about the same size as a sheet of A4 paper & about 5cm thick. The term Notebooks has superseded the term laptop that generally referred to a portable PC. The original laptops were bulky & quite heavy.
LAPTOP
Meaning of LAPTOP in English
English glossary of Internet and PC terminology. Английский глоссарий Интернет и ПК терминологии. 2012