black hole (n.)

in astrophysics, 1968, probably with awareness of the notorious Black Hole of Calcutta, incident of June 19, 1756, in which 146 British POWs taken by the Nawab of Bengal after the capture of Ft. William, Calcutta, were held overnight in a punishment cell of the barracks (meant to hold 4 people) and all but 23 perished.