Balustrade

[Sarah]

A row of balusters topped by a rail, serving as an openparapet, as along the edge of a balcony, terrace, bridge, staircase,or the eaves of a building.

[Julian]

a set of posts or a screen to prevent people from falling over the edge of stairs, a balcony, etc., often with a wooden, metal, or stone bar on top that you can hold:

[Sommer]

A railing supported by balusters, especially an ornamental parapet on a balcony, bridge, or terrace.