“Tread” is the technical term for the surface part of the steps of a staircase. It is literally the part you tread or walk on. Put more simply, it is the top part of the step, the part you see
Stair Tread and Options for Installation

“Tread” is the technical term for the surface part of the steps of a staircase. It is literally the part you tread or walk on. Put more simply, it is the top part of the step, the part you see