Railing on a staircase (8)
(Other definitions for banister that I've seen before include "support at hand on flight" , "Upright supporting handrail of stairs" , "Staircase railing" , "Rail beside a staircase" , "Stair-rail" .)
(Other definitions for balustrade that I've seen before include "Parapet" , "Stair rail and its supports" , "Row of short pillars with coping" , "Railing supported on pillars" , "feature of terrace, perhaps" .)