Fiberboard is the American spelling of fibreboard. Same material: a board made by pressing tiny wood fibers together, usually with glue, into a cheap, flat sheet. Builders and furniture factories like it for the back of a bookshelf, a cupboard door, a wall panel — not real planks. It does not like water: it swells and crumbles. One common kind is MDF, a smooth, dense sheet. Though actually, in a Taiwan hardware shop people often say 密集板 for MDF, and 纖維板 for the wider group; they are not always the same piece on the shelf. It is not fiberglass (that is glass threads, often in plastic).

纖維板（美式拼法）。台灣裝潢口語的「密集板」多半是其中一種（MDF）。