WHY LAPTOP ?

Sometimes before I fall asleep I think of things and I really don't know why. This time I wondered why a laptop is called laptop and not kneetop or legtop or bellytop and who gave this name ? The next morning I wanted to find out ! No way ! I googled, I wikipediaed they all explained how a laptop works, its size, and that it is portable. All things I knew too.

In a dictionary I found following explanation :

lap·top
[lap-top] 
noun
a portable, usually battery-powered microcomputer small enough to rest on the user's lap.

While in Wikipedia and everywhere else  the definition is :

A laptop computer is a portable personal computer light and small enough to sit on a person's lap. The main utility of a laptop computer is that it allows a person to travel with their computing resource.

At least now I know the difference ! In a dictionary a laptop rests in other definitions it sits !