A contour line drawing, or simply contour drawing, is an outline of the main features in a drawing. Some main features may be sketched out, but the purpose of a contour drawing is to determine the mass and size that the final picture will have.
Contour drawing can be done from scratch or from an existing piece. A beginner can use contour drawing to learn the basics of drawing by completing outlines of highly technical pieces. In time, the drawer can start to progress to adding more details on top of the contours. A special type of contour drawing is "blind" contour drawing, which involves not looking at the paper while drawing.