Buttress.
A buttress is a solid support that sticks out from a wall to stop it being pushed sideways. In simple terms, it's how masonry buildings "fight" the outward thrust from arches, vaults, wind, or uneven loads.
Definition (Buttress meaning / Buttress in architecture)
The buttress meaning is easiest to get with a simple image: a tall stone wall is great at carrying weight straight down, but it struggles when forces push it sideways. And arches and vaults don't only push down—they also create outward thrust. That sideways push is called lateral thrust, and it can crack a wall or make it lean over time.
A buttress solves this by giving the wall extra "shoulder strength." It adds mass and a wider base outside the wall so the wall is less likely to tip or split. Technically, a buttress improves stability by increasing the resisting moment against overturning and by helping keep the line of thrust safely within the wall-and-support system.
Buttress design (types and how they work)
In buttress design, the goal is always the same—catch the sideways force and send it safely into the ground—but the form can vary.
- —Solid buttress
A simple projecting mass that thickens the wall. It's straightforward and effective, especially where loads are concentrated.
- —Stepped buttress
A buttress that becomes thicker toward the base. This matches real structural behavior: forces typically accumulate downward, so more mass is needed lower.
An arched "arm" that transfers thrust from a high wall to a separate pier. Structurally, it supports the wall right where the thrust happens (often high up) while keeping space open below for larger windows and circulation.
Buttress in construction (where you still see it today)
Modern steel and reinforced-concrete buildings often resist lateral forces with frames, cores, and shear walls, so classic buttresses aren't always necessary. But buttresses are still very relevant in: historic preservation, seismic retrofits, buttressed retaining walls, and designs that intentionally express structural logic.
Buttress synonym (and common confusion)
There isn't a perfect everyday buttress synonym because the term is quite specific. People sometimes use "support" or "brace," but those are generic.
Common confusion
- —Buttress vs. shear wall
A shear wall is a structural wall designed to resist lateral loads inside a building frame; a buttress is an external support added to stabilize a wall.
- —Buttress vs. retaining wall
A retaining wall holds back soil; a buttress supports a wall against thrust or wind (though buttressed retaining walls exist).