A parapet (from the Italian parapetto and/or the French parapet, from Italian para, imperative of Italian parare (to cover, defend) and petto (breast), ultimately from the Latin pectus (breast); the Germans use the term Brustwehr (breast-defence)) consists of a dwarf wall along the edge of a roof, or round a lead flat, terrace walk, etc., to prevent persons from falling over, and as a protection to the defenders in case of a siege.

Parapets are either plain, embattled, perforated or panelled. The last two are found in all styles except the Romanesque.

• Plain parapets are simply portions of the wall generally overhanging a little, with a coping at the top and corbel table below.
• Embattled parapets are sometimes panelled, but oftener pierced for the discharge of arrows, etc.
• Perforated parapets are pierced in various devices as circles, trefoils, quatrefoils and other designs so that the light is seen through.
• Panelled parapets are those ornamented by a series of panels, either oblong or square, and more or less enriched, but not perforated. These are common in the Decorated and Perpendicular periods.

Compare breastwork .

Original text from the 1911 Encyclopaedia Britannica

Many people believe every house should have a parapet: "When you build a new house, make a parapet around your roof so that you may not bring the guilt of bloodshed on your house if someone falls from the roof." -- Deuteronomy 22:8 (NIV)