Meaning of antitwilight arch

an•ti•twi'light arch"

Pronunciation: (an"tē-twī'līt, an"tī-), [key]
  1. a narrow band, pink or with a purple cast, that sometimes appears at twilight just above the horizon opposite the sun. Also called
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.