"support for a railing," c.1600, from Fr. balustre, from It. balaustro "pillar," from balausta "flower of the wild pomegranate," from Gk. balaustion (perhaps of Sem. origin, cf. Aram. balatz "flower of the wild pomegranate"). Staircase uprights had lyre-like double curves, like the calyx tube of the pomegranate flower.