Baluster (through the Fr. from the Ital. balaustro, so-called from a supposed likeness to the flower of the βαλαύστιον, or wild pomegranate; the word has been corrupted in English into "banister"), a small moulded shaft, square or circular, in stone or wood and sometimes in metal, supporting the coping of a parapet or the rail of a staircase, an assemblage of them being known as a balustrade. The earliest examples are those shown in the bas-reliefs representing the Assyrian palaces, where they were employed as window balustrades and apparently had Ionic capitals. They do not seem to have been known to either the Greeks or the Romans, but early examples are found in the balconies in the palaces at Venice and Verona. In the hands of the Italian revivalists they became features of the greatest importance, and were largely employed for window balconies and roof parapets.
The term "baluster shaft" is given to the shaft dividing a window in Saxon architecture. In the south transept of the abbey at St Albans, England, are some of these shafts, supposed to have been taken from the old Saxon church. Norman bases and capitals have been added, together with plain cylindrical Norman shafts.