What denotes the visual characteristics of an object’s contour in design?

The correct choice defines the visual characteristics of an object's contour as "shape." Shape refers specifically to the two-dimensional outline or contour of an object, distinguishing it from other attributes such as form, which encompasses volume and three-dimensional aspects. In design, shape is vital as it determines the perception of objects, influences aesthetics, and plays a significant role in functionality.

While volume relates to the three-dimensional space that an object occupies, and form combines both the shape and volume of an object, it is the shape that directly pertains to the outline or contour experienced visually. Texture, on the other hand, refers to the surface quality of an object, affecting how it feels and can also impact how it is visually perceived but does not define the outline itself. Thus, understanding shape is crucial in design since it is fundamental to how objects are recognized and interpreted visually.