When it comes to 3D I see object dimensions described with attributes: - width - height - length
When it comes to 2D I'm a bit confused, sometimes I see width,height sometimes width,length
For example when defining a 2D canvas in a Adobe software you use width & height.
But if I make some research in the net it seems more correct to use width,length for 2D then height will be added as 3rd axis.
Maybe it depends also if the object is usually intended to be horizontal or vertically oriented. (That would explain a why using height for a canvas on a monitor)
But what if it's a paper sheet, where actually u don't know if it's intended for horizontal or vertical positioning?