D defs.my
Entry 1 sense Webster, 1913

Obtenebration

· Ob·ten·e·bra·tion · IPA
01 n. The act of darkening; the state of being darkened; darkness.
  1. 1.
    The act of darkening; the state of being darkened; darkness.[Obs.]
    “In every megrim or vertigo, there is an obtenebration joined with a semblance of turning round.” Bacon.