clap ‧ board /ˈklæpbɔːd $ ˈklæbərd, ˈklæpbɔːrd/ BrE AmE noun [uncountable and countable]
[ Date: 1600-1700 ; Origin: Part translation of Dutch klaphout , from klappen 'to split' + hout 'wood' ]
especially British English a set of boards used to cover the outside of a building, or one of these boards:
clapboard houses