I just found out that what I used to slide down was not a bannister (which is a family
name), and not even a banister. It was a baluster, or balustrade.
baluster - 1602, from It. balaustro (see balustrade).
balustrade - 1644, from Fr., from It. balaustro "pillar," from
balausta "flower of the wild pomegranate," from Gk.
balaustion. Staircase uprights had lyre-like double curves,
like the calyx tube of the pomegranate flower