baluster

puola, kaidepuu, balusteri puhekieltä  A short column used in a group to support a rail, as commonly found on the side of a stairway; a banister.
(quote-book)
2004, (w), (w), Bloomsbury, 2005, Chapter 17 (i),

Nick looked at the floor, and at the rhythm of the black-and-gilt S-shaped balusters.