Advertisements now say notebooks, sometimes. Is this the new term for laptop? Are the two actually different creatures? Are laptops going the way of, first Beta and now VHS, movies?
My understanding is that a notebook computer is the same size (in plan) as a sheet of A4 paper. A4 is a paper size used internationally except west of the Atlantic, east of the Pacific, and probably north of Mexico and south of Canada. If they are smaller than that they are termed sub-notebooks.
It's a little bigger than 8-1/2 x 11. Just enough bigger that you have to drag out the A4 paper and load up the tray if you want to make a copy that has the fine print at the top and bottom.
It's 210 mm x 297 mm (that's a trimmed sheet). I forget why those particular dimensions, but someone probably knows. I know the basic size is the A0 size which has a plan area of 1 square metre, if you fold A0 in half you have A1, fold it again and you have A2 etc.