Definitions
1.nounA narrow board, usually thicker at one edge than the other, used as siding for houses and similar structures of frame construction.
2.nounSuch boards, arranged horizontally and overlapping with thick edge down, collectively, as siding.
3.nounAn oak board of a size used for barrel staves.
4.verbTo cover with clapboards."to clapboard the sides of a house"