A buttress refers to a structural support element, typically an external masonry or reinforced concrete structure, that provides additional strength and stability to a wall or building. Buttresses are commonly used in architectural designs, especially in Gothic and Romanesque styles, to counteract the lateral forces exerted on tall or heavy walls. They are usually built against or projecting from the wall, providing support by transferring the structural loads, such as the weight of a roof or upper walls, downwards and outwards to the ground.