- Chiefly Northeastern U.S. a long, thin board, thicker along one edge than the other, used in covering the outer walls of buildings, being laid horizontally, the thick edge of each board overlapping the thin edge of the board below it.
c.1520, partial transl. of M.Du. klapholt (borrowed into Eng. 14c.), from klappen "to fit" + L.Ger. holt "wood, board."
"Like the other boats, she was clinker-built—which meant that the wooden planks of her hull overlapped in the fashion of a clapboard house."
- Hampton Sides, In the Kingdom of Ice: The Grand and Terrible Polar Voyage of the USS Jeannette