backerboard

Etymology

From backer + board.

backerboard means A board used behind or under other material, often as support.; Boards used as underlayment for tile, plaster, or other materials. Lexicurio rates it Sui generis — a strength score of 97 out of 100.

noun

A board used behind or under other material, often as support.; Boards used as underlayment for tile, plaster, or other materials.“A tile setter mounts colorful American-Olean ceramic tile on a new gypsum backerboard in a motel bathroom...”
A board used behind or under other material, often as support.; A sacrificial board placed behind or under a board being drilled or sawn, so as to prevent blowouts. (Usually scrap ends reused for such purpose.)
A board used behind or under other material, often as support.; Sheets of cardboard or similar material used to preserve or display books, magazines, art prints, etc.“Campos likes this shop not only because it's just a few blocks from his Glendale home but because of the little extras that Brown throws in, like wrapping each comic book with a backer board in a plastic protective sleeve.”