zodiacal : Idioms & Phrases

• 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
  

WordNet

• a luminous tract of the sky, of an elongated, triangular figure, lying near the ecliptic, its base being on the horizon, and its apex at varying altitudes. It is to be seen only in the evening, after twilight, and in the morning before dawn. It is supposed to be due to sunlight reflected from multitudes of meteoroids revolving about the sun nearly in the plane of the ecliptic.

Webster 1913