What is the difference between a banister and a baluster? A banister is the railing (handrail) on a set of stairs. It sets on top of the vertical pieces of wood called “balusters” or “spindles”. Balusters are used for aesthetics and stability. They are also used for safety reasons – for example, a child to not be able to squeeze through and fall. There is a specified measurement to set the balusters side by side – usually less than 4 inches apart.