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 Fort William were held overnight in a punishment cell of the barracks (meant to hold 4 people) and all but 23 perished.

also aquafortis, old commercial name for "diluted nitric acid," c. 1600, Latin, literally "strong water;" for the elements, see aqua- + fort. Also see aqua. So called for its power of dissolving metals (copper, silver) which are unaffected by other agents.

"an occasional pastime, an activity other than that for which one is well-known, or at which one excells," 1963, from French, literally "Ingres' violin," from the story that the great painter preferred to play his violin (badly) for visitors instead of showing them his pictures.

Une légende, assez suspecte, prétend que le peintre Ingres état plus fier de son jeu sur le violon, jeu qui était fort ordinaire, que de sa peinture, qui l'avait rendu illustre. [Larousse du XXe Siecle, 1931]