Backband: Narrow, rabbeted molding installed on the outside edge and corner of an interior window or interior door casing. Used to create a heavy trim appearance.
Backing Board: (1) In two layer drywall systems, the base panel of gypsum wallboard. Not suitable as finiah surface, since it uses grey liner paper facing.
(2) In a cutting operation like sawing or routing, a board put behind the work piece board so the the first board will not chip out from the blade moving out of it.