1 (geometry) A polyhedron with parallel ends of the same size and shape, the other faces being parallelogram-shaped sides.  A transparent block in the shape of a prism (typically with triangular ends), used to split or reflect light.
To the Jews, solar eclipses meant that the moon was passing between the sun and the earth, thereby blocking the suns light. Notwithstanding the physical explanation of a solar eclipse, there is also spiritual significance to it: At the time when the sun is eclipsed, it is an unfavorable period for the world. A parable: This can be compared to a human king who made a feast for his subjects, and placed a lantern before them.
The moon always looks as like it is constantly changing, this reminds of the fluidity and inconsistency of life. The moon is also symbolic of the never ending circle of nature of time and karma. Karma is a circle that reminds us what goes around comes around. The moon symbolizes feminine power and fertility.