The portcullis.
it means vertical sliding gate that protects a castle.
If it drops it is called a portcullis.
The Gate House controls the entrance through the wall and into the castle. The castle is the name for the entire fortified building. The gate house, keep, chapel, wall (etc) are different parts of the castle.
The gatehouse is the structure that defends the main gate, so the gatehouse is always at the entrance.
Bharatpur.
A castle would often have a large, heavily fortified gate. A smaller gate, sometimes with a grille, let into this large gate, was called a wicket.
A portcullis is gate that drops in front of a Castle door. A drawbridge is a moveable structure that allows access across a moat to the Castle door.
Well, a gatehouse is a part of a castle that is heavily defended. The gate house includes a drawbridge and maybe murder holes. If attackers get in, defenders could shower them with rocks, red hot sand, or boiling water and oil through the muder holes in the ceiling. A heavy metal portcullis protected the gate house enterence
The analogy for "gate," "castle," and "tentacle" could represent different levels of protection or influence. The "gate" symbolizes an entrance or barrier, the "castle" signifies a stronghold or fortified position, and the "tentacle" suggests an extending reach or grasp into various areas. Together, they illustrate a progression from simple access to complex control and dominance.
it is called a portcullis
Other names for an entrance gate are: access gate entry gate
Entrance gate