1. In a stairway, the width of a step, measured from the face of one riser to the face of the next, and not including the nosing. 2. The horizontal distance covered by a flight of steps. 3. The length of the horizontal projection of a sloping member such as a rafter when in position. 4. A temporary planked scaffold for walking or wheeling materials. 5. That portion of a pipe or fitting continuing in a straight line in the direction of flow in the pipe to which it is connected. 6. An appreciable length of straight or nearly straight piping.