A contour drawing shows the outlines, shapes and edges of a scene, but omits fine detail, surface texture, color and tone.
A contour line drawing is deliberately and slowly executed.
It defines edges, including planes, interior, and exterior edges. Lines are not sketchy and usually show details.
The purpose of contour drawing is to emphasize the mass and volume of the subject rather than the detail; the focus is on the outlined shape of the subject and not the minor details.