An interception or obscuration of the light of the sun,
   moon, or other luminous body, by the intervention of some other body,
   either between it and the eye, or between the luminous body and that
   illuminated by it. A lunar eclipse is caused by the moon passing
   through the earth's shadow; a solar eclipse, by the moon coming between
   the sun and the observer. A satellite is eclipsed by entering the
   shadow of its primary. The obscuration of a planet or star by the moon
   or a planet, though of the nature of an eclipse, is called an
   occultation. The eclipse of a small portion of the sun by Mercury or
   Venus is called a transit of the planet.