fiberboard: wallboard composed of wood chips or shavings bonded together with resin and compressed into rigid sheets
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
equilibrium law: (chemistry) the principle that (at chemical equilibrium) in a reversible reaction the ratio of the rate of the forward reaction to the rate of the reverse reaction is a constant for that reaction