Bar Lock
A Bar Lock is a kind of lock on a door usually found in all dungeons. These locks cannot be opened unless a certain task is completed. For example, defeating enemies, moving a block/pot onto a Switch, etc. They are called bar locks because of the metal bars that drop down in front of the door to prevent Link from opening it. In a mini-Boss room, the bars drop down when Link enters the room and lifts up when the enemy is defeated.
See also: