Parapet n. : A low wall, especially one serving to protect the edge of a platform, roof, bridge, or the like.

Parapet n. : A wall, rampart, or elevation of earth, for covering soldiers from an enemy's fire; a breastwork. See Illust. of Casemate.

Example:
What is the difference between a Parapet and a rampart?

Taxonomy
parapet, roof, Bridge parapets, free encyclopedia, portion, Fire Wall, perforated, the wall, exterior wall, roof surface, flat roof, roof slopes, restraint systems, Building Code, search, guard, copyright violations, factual inaccuracies.

Defination from the web:
parapet is a wall-like barrier at the edge of a roof, terrace, balcony or other structure. ... Instead an 18-inch brick parapet was required, with the roof set behind. ... Exterior walls that require to be fire protected are often required to have a parapet, but there are exceptions. ...