[W/K] :: Leveling staff

  Leveling \Lev"el*ing\, n. [Written also levelling.]
     1. The act or operation of making level.
        [1913 Webster]
  
     2. (Surveying) The art or operation of using a leveling
        instrument for finding a horizontal line, for ascertaining
        the differences of level between different points of the
        earth's surface included in a survey, for establishing
        grades, etc., as in finding the descent of a river, or
        locating a line of railroad.
        [1913 Webster]
  
     Leveling instrument. See Surveyor's level, under Level,
        n.
  
     Leveling staff, a graduated rod or staff used in connection
        with a leveling instrument for measuring differences of
        level between points.
        [1913 Webster]