What does "twilight" mean?

Twilight: faint light; a dubious or uncertain medium through which anything is viewed. As when the sun . . . from behind the moon, In dim eclipse. disastrous twilight sheds. Milton. The twilight of probability. Locke.

Additional senses

  1. 2.Seen or done by twilight. Milton.
  2. 3.Imperfectly illuminated; shaded; obscure. O'er the twilight groves and dusky caves. Pope.

Sources