degrau
Degrau is a term used in Portuguese and other languages to refer to a single step of a staircase. In architectural and construction contexts, a degrau is the horizontal surface a person steps on, called the tread, and its vertical face, the riser, which rises to the next level. Stairs are designed to provide safe ascent and descent, with the size and shape of degraus governed by building codes and ergonomic guidelines. The function of degraus is to translate vertical height into a sequence of shallow climbs, enabling access between different levels of a structure. Variations exist across regions and types of stairs.
In mathematics and related fields, degrau can refer to a step function, also called a Heaviside function
Other uses and considerations: The concept of a degrau appears in descriptions of thresholds, levels, or progressions