A contour is a line that forms an edge. Contour lines are three-dimensional (3D); they surround and describe the internal forms and external edges of an object, giving it shape and volume. This is different from an outline, which is two-dimensional (2D), and only describes the external edge (perimeter) of an object.
A contour drawing uses contour lines to represent subject matter. It has a three-dimensional quality, and indicates the thickness as well as height and width of the forms and/or edges it describes. Contour drawing exercises are designed to improve visual concentration & hand/eye coordination.
Continuous Line- drawing using a single continuous-line, without lifting your drawing tool from the page.
Blind Contour- continuous line drawing made without looking at the paper; you keep your eyes on whatever you're drawing.