Tread = the horizontal component/the part you walk on. Riser = the vertical component between each tread. You will have one more riser than tread in each run (section) of steps.

Tread = the horizontal component/the part you walk on. Riser = the vertical component between each tread. You will have one more riser than tread in each run of steps.

NOTE: If you have two landings within your staircase, this question is referring to the middle steps (this may just be a single riser between the 2 landings) - we'll ask for the uppermost steps/section later.