What is a single vertical thickness of masonry called, designed to improve exterior appearance?

A single vertical thickness of masonry that is primarily designed to enhance the exterior appearance of a structure is referred to as a veneer wall. Veneer walls serve as a decorative surface that provides aesthetic appeal while often being supported by a structural backing. They do not bear significant loads like a load-bearing wall but instead are utilized for their visual and design qualities.

In contrast, a load-bearing wall supports structural loads and is essential for the stability of a building. A retaining wall is primarily designed to hold back soil or water, providing support for elevated ground; it does not focus on aesthetics. A shell wall, while it may refer to a type of wall that provides an outer covering, does not specifically pertain to the aesthetic function of a veneer in the same way that a veneer wall does. Therefore, veneer wall is the term that accurately describes the type of wall intended to improve exterior appearance.