portcullis
noun [ C ] uk/ˌpɔːtˈkʌl.ɪs/ us/ˌpɔːrtˈkʌl.ɪs/
（城堡的）吊闸，吊门
a strong gate made of bars with points at the bottom that hangs above the entrance to a castle and in the past was brought down to the ground in order to close the entrance against enemies