plasterboard: wallboard with a gypsum plaster core bonded to layers of paper or fiberboard; used instead of plaster or wallboard to make interior walls
wallboard: a wide flat board used to cover walls or partitions; made from plaster or wood pulp or other materials and used primarily to form the interior walls of houses
ethyl: the univalent hydrocarbon radical C2H5 derived from ethane by the removal of one hydrogen atom