Which attribute describes the characteristics through which an object's surfaces define its shape?

The correct answer is the articulation of forms. This term refers to the way that surfaces and their characteristics are organized to create three-dimensional shapes and volumes in architecture. When discussing the articulation of forms, the focus is on how edges, curves, and the overall arrangement of surfaces contribute to the perception and definition of an object's shape.

Articulation emphasizes the relationship between different parts of a structure and how they interact with light and shadow, as well as visual and tactile qualities, thereby enhancing the overall aesthetic and functional experience of the design. This concept is crucial in architecture, as it helps convey the intention of a design and influences how the space will be perceived by users.

In contrast, while attributes like edge and surface contribute important characteristics to a shape, they do not encapsulate the full idea of how surfaces work together to define an object's overall form and presence. Position refers more to the location of an object rather than the shape it defines through its surfaces. Thus, the articulation of forms provides a more comprehensive understanding of the relationship between surfaces and shape in architecture.