A type of lightweight construction material made from wood fibers, used as wallboard or insulation in buildings.
Compound of beaver (the animal, from Old English beofer, ultimately from Indo-European root) and board (from Old English bord). Named beaver + board because it was supposedly as industrious and useful as a beaver in construction.
Beaverboard was a trademark product from the early 1900s that became so popular people used the name generically, much like how people say 'Band-Aid' for any adhesive bandage—it's a perfect example of a brand name that almost became a common word.
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