DICT.TW Dictionary Taiwan

 black hole A dungeon or dark cell in a prison; a military lock-up or guardroom; -- now commonly with allusion to the cell (the Black Hole) in a fort at Calcutta (called the Black Hole of Calcutta), into which 146 English prisoners were thrust by the nabob Suraja Dowla on the night of June 20, 1765, and in which 123 of the prisoners died before morning from lack of air.
    A discipline of unlimited autocracy, upheld by rods, and ferules, and the black hole.   --H. Spencer.
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 Black Hole of Calcutta
      n : a dungeon (20 feet square) in a fort in Calcutta where as
          many as 146 English prisoners were held overnight by
          Siraj-ud-daula; the next morning only 23 were still alive