From Longman Dictionary of Contemporary Englishparapetpar‧a‧pet /ˈpærəpət, -pet/ noun [countable] 1 TBBa low wall at the edge of a high roof, bridge etc2 PMa protective wall of earth or stone built in front of a trench in a war3 → put/stick your head above the parapet
Examples from the Corpus
parapet• The double-decker smashed through a fence and ended up perched precariously on a bridge parapet at Brighouse, West Yorkshire.• Once you put your head above the parapet these people clearly shot at it.• As he reached the foot of the bleak stone steps, a single gunman opened fire from the parapet around the stairway.• I got up and went to the corner of the parapet, from where I could see in three directions.• I shifted unobtrusively, to crane a look over the parapet.• Choir and audience wave to each other when the singing is over, some of the little boys leaning perilously over the parapets.• Corrigan watched the parapet above them.Origin parapet (1500-1600) Italian parapetto, from parare “to protect” + petto “chest” 