1Of the nature of a dado; (of a wall or room) provided with a dado.
2North American, Woodworking and Joinery. Designating a joint in which the edge of a piece of wood is fixed into a channel or slot cut across the grain in the face of another piece of wood; designating a channel or slot of this kind.
Mid 18th century; earliest use found in William Pain (fl. 1743–1794), writer on architecture. From dado + -ed.