counterglow

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. See gegenschein.

Century Dictionary and Cyclopedia

1. n. The light from the eastern sky after the sun has set: an apparent reflection of the sunset twilight glow, but really the independent illumination of the eastern atmospheric dust and haze by sunbeams that pass far above the observer through the upper atmosphere when the sun is below the horizon. The lower limit of the counter-glow is the twilight-arch.
2. n. A patch of extremely faint luminosity in the heavens always opposite to the sun. It is supposed to be connected with the zodiacal light.

Wiktionary

1. n. The gegenschein.

GNU Webster's 1913

1. n. (Astron.) An exceedingly faint roundish or somewhat oblong nebulous light near the ecliptic and opposite the sun, best seen during September and October, when in the constellations Sagittarius and Pisces. Its cause is not yet understood. Called also Gegenschein.

WordNet 3.0

1. n. a faint spot of light in the night sky that appears directly opposite the position of the sun; a reflection of sunlight by micrometeoric material in space