Clapboard 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. Typically found in abundance in New England homes. A board may be a: piece of lumber (or other rigid material made of wood), milled or sawn flat surfboard, skateboard, or snowboard (often made of fibreglass) commission or committee, such as an executive board of directors or a (sometimes rather supervisory) board of governors bulletin board system or other... This article is about the house covering. ...