a wall built or arranged to provide an air space within the wall (with or without insulating material), in which the inner and outer materials are tied together by structural framing
A cavity wall is a wall that consists of two separate walls with a space between them. Cavity walls help to keep out noise and cold. cavity wall insulation. a wall consisting of two walls with a space between them to keep out cold and noise. In architecture, a double wall consisting of two wythes (vertical layers) of masonry separated by an air space and joined together by metal ties. The cavity allows moisture that penetrates the exterior wythe to drain. Cavity walling is used as both non-load-bearing infill for framed buildings and for bearing-wall construction
a carton or fitment where the sidewalls are constructed so as to form a hollow frame effect
Wall of two leaves effectively tied together with wall tie with a space between them, usually at least 50mm wide