British EnglishBrEDHH soft material that you put between a carpet and the floor 〔置于地板与地毯之间的〕地毯垫毡
Examples from the Corpus
underfelt• Together with thick carpet and underfelt, it should go a long way to pleasing the occupants of the flat below.• It is loose laid on underfelt like an enormous rug with a surround of polished wooden floors.