Which term refers to a three-dimensional object in design?

The term that refers to a three-dimensional object in design is "Form." In the context of design, "form" encompasses the overall shape and structure of an object, considering its three-dimensional characteristics such as depth, width, and height. It captures the physicality of the object, including how it occupies space and how it can be viewed from different angles.

In contrast, "shape" typically refers to the two-dimensional outline or contour of an object, often lacking the depth that form provides. "Volume" pertains specifically to the amount of space an object occupies, which is related but distinct from the concept of form. "Aspect" generally refers to a particular feature or part of something, which does not encompass the entirety of a three-dimensional object as form does. Therefore, form is the most accurate term to denote a three-dimensional object in design contexts.