clap·board 
/ˈklæbɚd, ˈklæpˌboɚd/ noun
plural clap·boards /ˈklæbɚd, ˈklæpˌboɚd/ noun chiefly US 1 [count] : a narrow board that is thicker at one edge than at the other and that is used to cover the outsides of buildings —called also (Brit) weatherboard 2 [noncount] : a set of narrow boards covering the outside of a building
▪ the house's decaying clapboard
▪ the house's decaying clapboard
— clapboard adjective always used before a noun
▪ clapboard siding ▪ a clapboard house/building [=a house/building that is covered in clapboards]
▪ clapboard siding ▪ a clapboard house/building [=a house/building that is covered in clapboards]
