What term describes the total horizontal distance covered by a stairway?

The term that describes the total horizontal distance covered by a stairway is the "run." In stair design, the run refers specifically to the horizontal length from the front edge of one step (or tread) to the front edge of the next step. It is a critical measurement, as it influences the overall configuration of the stairway, affects how steep the stairs are, and plays a significant role in ensuring safety and comfort for users.

The rise, on the other hand, refers to the vertical distance from one step to the next. Tread depth, while related to the design of individual stair treads, pertains to the specific depth of each tread rather than the total horizontal span of the entire stairway. A stairwell describes the vertical space that a staircase occupies and is not a measurement of distance covered horizontally. Understanding these terms helps in accurately assessing and designing staircases that meet building codes and safety standards.