Открываем википедию: A laptop, often called a notebook computer or just notebook, is a small, portable personal computer with a "clamshell" form factor.
Terminology variants
The terms laptop and notebook are used interchangeably to describe a portable computer in English, although in some parts of the world one or the other may be preferred. There is some question as to the original etymology and specificity of either term—the term laptop appears to have been coined in the early 1980s to describe a mobile computer which could be used on one's lap, and to distinguish these devices from earlier, much heavier, portable computers (informally called "luggables"). The term "notebook" appears to have gained currency somewhat later as manufacturers started producing even smaller portable devices, further reducing their weight and size and incorporating a display roughly the size of A4 paper; these were marketed as notebooks to distinguish them from bulkier laptops. Regardless of the etymology, by the late 1990s, the terms were interchangeable.

https://en.wikipedia.org/wiki/Laptop

Все вроде понятно объясняется.)

Тогда следующий вопрос - когда он появился?

Видимо в тот момент когда начали использовать лэптопы как записные книжки для работы) и я думаю так же позиционировали их на рынке)

Darth Kenoby Аж самому стало интересно))

если дальше по вики потыкать))
https://techspirited.com/notebook-vs-laptop

1989 год) компания NEC)

The NEC UltraLite was touted as the world's first notebook PC when it was introduced in 1989. At 4.4 lbs, it was a lot lighter than average laptops back then and thus came across as a benchmark, which helped differentiate between laptops and the new breed of portable computers -- notebooks.