Door

Doors are recurring objects in The Legend of Zelda series. They are found throughout dungeons, but also used to enter homes and other buildings. In dungeons, doors can become barred or chained, and Link must complete a goal within the room he is stuck in in order to 'unlock' them.

Big Doors
Big Doors (sometimes referred to as Boss Doors) are primarily used to guard the boss of a dungeon's lair. In each game, Link must find a Boss Key (or, in specific dungeons, a Nightmare Key or the Bedroom Key) in a treasure chest and use it to unlock the boss's lair. Additionally, in The Minish Cap, multiple Big Doors can be found throughout dungeons.

Locked Doors
Locked Doors are doors in dungeons found usually chained shut with a keyhole in them. These doors can usually only be opened with a Small Key. Sometimes, however, when Link enters a room, all doors will lock and he must complete a certain goal to move on. In The Legend of Zelda, it is sometimes necessary for him to push a block in a certain direction to move on.