There are two main types of stair parts: the ones that make up the stair and the ones that form the balustrade. The stair is made up of four parts: stringers, risers, treads and the swell step or starter step. 

    The stringer is the part of the stair that runs along the side of the stairs and helps to support the part of the stairs you walk on. The risers are the stair parts that form the vertical part of the stair. The treads are the stair parts that are the horizontal part of the stair you put your foot on. The swell step or starter step is the first step on a staircase.