%furring%

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. [ 1913 Webster ]

2. (Shipbuilding) Double planking of a ship's side. [ 1913 Webster ]

3. A deposit from water, as on the inside of a boiler; also, the operation of cleaning away this deposit. [ 1913 Webster ]