What is the term for a structure that provides support against a wall?

The term "buttress" refers to a structure built against a wall to provide support and stability. Buttresses are commonly used in architecture to counteract the lateral forces exerted on walls, particularly in large structures like cathedrals and castles. They help to prevent the walls from bending or collapsing under pressure, allowing for taller and more expansive designs.

In contrast, other terms like "arch," "pillar," and "column" serve different purposes in architecture. An arch is a curved structure that spans an opening and distributes weight, while a pillar typically refers to a vertical support structure that can stand independently, often used to support a section of a building or roof. A column, much like a pillar, is a vertical and cylindrical structure that supports loads, but it may also serve decorative purposes in designs. None of these fulfill the specific role of providing external support against a wall in the same way a buttress does. Therefore, identifying a buttress as the key architectural feature for that support role is essential in understanding structural design principles.