wall

An upright structure of masonry, wood, plaster, or other building material serving to enclose, divide, or protect an area, especially a vertical construction forming an inner partition or exterior siding of a building.

A continuous structure of masonry or other material forming a rampart and built for defensive purposes.

A structure of stonework, cement, or other material built to retain a flow of water.

Something resembling a wall in appearance, function, or construction, as the exterior surface of a body organ or part.

Something resembling a wall in impenetrability or strength.