What is the term for the horizontal part of the stairs that one steps on?

The correct term for the horizontal part of the stairs that one steps on is "tread." Treads are the flat, horizontal surfaces of each step where individuals place their feet while ascending or descending stairs. They are essential for safety as they provide the necessary footing to prevent slips and falls.

In stair design and construction, treads are often designed with specific dimensions to ensure comfort and safety during use. For instance, building codes often specify minimum tread depth so that individuals have enough space to place their feet securely.

Understanding the terminology associated with stair components is critical for anyone involved in construction, architectural design, or safety inspections, as proper identification helps ensure compliance with safety regulations and building codes.