Balustrade n. : A row of balusters topped by a rail, serving as an open parapet, as along the edge of a balcony, terrace, bridge, staircase, or the eaves of a building.

Example:
Where can I find a vintage push-pull switched light fixture that mounts onto staircase Balustrade base post?

Taxonomy
baluster, balustrade, shaft, wood baluster, lathe, banister, Baluster Spacing, architecture, free encyclopedia, open flower, stone balusters, palaces, legs, vase shape, Stone, Michelangelo, Balustrade Systems, pomegranate.

Defination from the web:
balustrade did not seem to have been known to either the Greeks or the Romans (Wittkower 1974), but baluster ... A vasiform balustrade crowns Michelangelo's Palazzo degli Conservatori on the Campidoglio, Rome ...