zodiacal light

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A faint hazy cone of light, often visible within the zodiacal band in the west just after sunset or in the east just before sunrise, apparently caused by the reflection of sunlight from meteoric particles in the plane of the ecliptic.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun astronomy A soft glow of white light extending upward from the horizon along the ecliptic, particularly in the tropics.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a luminous tract in the sky; a reflection of sunlight from cosmic dust in the plane of the ecliptic; visible just before sunrise and just after sunset