fibreboard

US fiberboard

noun

a building material made of compressed wood or other plant fibres, esp one in the form of a thin semirigid sheet

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012