something that forms the back or is placed at or attached to the back of anything to support, strengthen, or protect it. Theater. a curtain or flat placed behind a window, entrance, or other opening in a stage set to conceal the offstage area. material for backing a joist or rafter. a bevel given to the outer and upper edge of a hip rafter. More @Wikipedia
Hover over any link to get a description of the article. Please note that search keywords are sometimes hidden within the full article and don't appear in the description or title.