Cost effective panel made from highly compressed wood fibres. Usually finished smooth on one side and textured on the reverse.
Hardboard is specifically designed and manufactured to be a low-value but versatile board. Cost of production is kept low by using the natural resin in the wood fibres to bond the board rather than synthetic adhesives. Other materials can be added during the production process depending on the desired usage. An example would be tempering the board with linseed oil to make it less susceptible to warping.