"This is called an oubliette. That's French for "a place of forgetting". Your quarters, My Lady. No gates, no bars, no locks. Just walls of air."
—Maligant, First Knight
In any case, there's bound to be much crying
But the oubliette alone will let you think while dying.
—The Sixth Book of Bokonon, Cat's Cradle
It's a place you put people... to forget about 'em!