From Longman Dictionary of Contemporary Englishportcullisport‧cul‧lis /pɔːtˈkʌlɪs $ pɔːrt-/ noun [countable] TBa strong iron gate that can be lowered over the entrance of a castle
Examples from the Corpus
portcullis• There were moments when it felt like a portcullis downward-slammed between herself and the human community.• Another one rose, like a portcullis.• Inside there was a portcullis of some dark metal.• At each end of the tanks are portcullis gates, which are opened and closed by hydraulic rams.• The parliamentary portcullis is featured above his head.• This is meant to convey a sense of security and privacy: the drawbridge is pulled up and the portcullis is dropped.• A connection was made to the stand pipe each time the portcullis end gates were raised.• The bridge was not up, the portcullis raised and the guard in the gatehouse evidently keeping warm before a fire therein. 