WAC 296-307-26006. Definitions that apply to this section

Nose or nosing. The part of a tread projecting beyond the face of the riser immediately below. Open riser. The air space between the treads of stairways without risers. Platform. An extended step or landing breaking a continuous run of stairs. Railing. A vertical barrier erected along exposed sides of stairways and platforms to prevent people from falling. The top part of the railing usually serves as a handrail. Rise. The vertical distance from the top of a tread to the top of the next higher tread. Riser. The upright part of a step at the back of a lower tread and near the leading edge of the next higher tread. Stairs or stairway. A series of steps. A series of steps and landings having three or more risers constitutes stairs or a stairway. Tread. The horizontal part of a step. Tread run. The horizontal distance from the leading edge of a tread to the leading edge of an adjacent tread. Tread width. The horizontal distance from front to back of tread, including nosing.