\Fur"ring\, n. 1. (Carp.) (a) The leveling of a surface, or the preparing of an air space, by means of strips of board or of larger pieces. See {Fur}, v. t., 3. (b) The strips thus laid on. 2. (Shipbuilding) Double planking of a ship's side. 3. A deposit from water, as on the inside of a boiler; also, the operation of cleaning away this deposit.