Dungeon
A dungeon is a room or cell in a castle to keep prisoners. Most dungeons are underground, others are high up in towers.
An oubliette is a type of dungeon that can be entered by using a trapdoor in the ceiling. People were thrown into an oubliette from the ceiling and left there to starve or dehydrate to death, making it akin to immurement.
A dungeon is known to be a place to keep prisoners, but can also be used as a place to store wine or other things that can be cooled.
In medieval times, dungeons were used to keep prisoners to torture and try to get information, or just to punish them for doing or saying something that typically went against societies beliefs or practices.
Dungeon Media
Diagram of an alleged oubliette found in the Bastille prison in Paris, from Viollet-le-Duc (1854–1868) the commentary [by le Duc?] speculates that the structure depicted, may actually have been a cold-storage chamber built to keep ice. If so, whether or not it was known to also have been used as an oubliette is not clear.
A dungeon door in the Zrinski Castle in Čakovec, Croatia
A "dungeon" map created for a tabletop roleplaying game
