What signifies a physical adjoinment in the context of abut?

The correct choice signifies the concept of abut in terms of physical adjoinment, which refers to the contact or connection between two adjoining structures. This definition aligns with the common usage of the term, particularly in fields such as architecture and construction, where two structures must be in proximity or directly touching for structural support or functional connection.

In this context, the idea of physical adjoinment is about the relationship between the two entities being connected or bordering each other, which is essential for understanding how structures work together. The other answer options present scenarios that either describe separation or different types of attachment that do not pertain directly to the concept of abut as it involves direct contact or adjacency.