What is the point of contact between mass and space called?

The point of contact between mass and space is referred to as "Form." In architectural terminology, form encompasses the physical shape and configuration of a structure, as well as its spatial relationship with the surrounding environment. It represents not only the aesthetics of the building's geometry but also how the mass (the physical substance of the building) interacts with the voids of space around it.

Understanding this concept is fundamental in architecture as it highlights how space is defined and experienced in relation to the built environment. In essence, form creates a dialogue between the solid components of a structure and the spaces that they outline or enclose. This relationship is critical for achieving balance, harmony, and functionality in architectural design. The other terms, such as volume, linear form, and architectural form, can describe various aspects of space and mass but do not directly encapsulate the specific relationship of contact between them as succinctly as "Form."