dungeon

Other forms: dungeons

That dank, stone-walled underground prison where wretched prisoners were kept manacled in medieval days? That was a dungeon, otherwise known as the "keep," and most familiar to us today from a million video games and movies.

In fact, the original meaning of dungeon was of something overground rather than underground, coming from the Old French term donjon, meaning the "great tower of a castle," and the underground meaning only came later. Rapunzel in the fairy tale was held captive in a tower rather than an underground cell and if she hadn't been, her long hair wouldn't have been much help in her escape.