Solarium may refer to: Sunroom, a room built largely of glass to afford exposure to the sun. A Terrace (building) or flat housetop. The Solarium Augusti, a monumental meridian line (or perhaps a sundial) erected in Rome by Emperor Augustus.
Noun. 1. cavity wall-a wall formed of two thicknesses of masonry with a space between them. wall-an architectural partition with a height and length greater than its thickness; used to divide or enclose an area or to support another structure; the south wall had a small window; the walls were covered with pictures.
The fluid-filled cavity within the body of most multicellular animals, except some invertebrates such as flatworms and cnidarians, that lies between the body wall and the digestive tract and is formed by the splitting of the embryonic mesoderm into two layers. Also called body cavity.