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.

An enhancement of the Zodiacal Light in the direction opposite the Sun, caused by a reflection of sunlight from meteoric material in interplanetary space. Particles which are opposite the Sun are 'fully' lit by its light, and reflect far more light than at other positions, in the same way that the full Moon is much brighter than other lunar phases.

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