What is countour drawing ?

This article is from Helen South,It is great to talk about What is contour Drawing.
The article is :
What Is Contour Drawing?
The first thing we do when beginning to draw is contour drawing, which is another name for drawing the outline. With contour drawing, we are focusing on the edges - the outside of an object or the line made by a fold or pattern. The line that goes across an object, hinting at the form, is called a cross-contour. Don't get fooled into using the line to draw light and dark. The WEIGHT of a line, that is, how dark and thick it is, will make it jump out from the paper (if it is a strong, dark line) or sink into the paper (if it is light or thin). This is useful when you are trying to give the impression of something being closer or further away.
When you look at an object, the shapes you see vary depending on your point of view. Take a simple mug, for instance - you know it has a perfectly cylindrical shape, with a circle top and bottom and sides that go straight up.
This is a good example of contour drawing