A parapet wall or balustrade surrounding the flat roofs of the houses, required to be built by a special law (Deuteronomy 22:8). In Jeremiah 5:10, it denotes the parapet of a city wall.

Noah Webster's New International Dictionary of the English Language

1. (n.) One of the solid upright parts of a parapet in ancient fortifications.

2. (n.) pl. The whole parapet, consisting of alternate solids and open spaces. At first purely a military feature, afterwards copied on a smaller scale with decorative features, as for churches.