Clapboard, also known as bevel siding or lap siding or weather-board (with regional variants as to the exact definitions of these terms), is a board used typically for exterior horizontal siding that has one edge thicker than the other and where the board above laps over the one below. It is often found in New England architecture.
Clapboard siding got its name from the Dutch Klappen, meaning to split. It was originally split by hand from logs in a radial manner. Later, the boards were radially sawn in a mill.