An eclipse phenomenon is a natural event that occurs when the Moon passes between the Sun and Earth, blocking out the Sun's light. The four crossword solutions for this term are UMBRA (5 letters), SHADOW (6 letters), HALO (4 letters), and CORONA (6 letters). The UMBRA is the darkest part of the Moon's SHADOW, where the Sun is completely blocked out. The SHADOW is the area of the Moon's SHADOW that is not in the UMBRA. The HALO is a ring of light that appears around the Moon during an eclipse. The CORONA is the outermost part of the Sun's atmosphere, which is visible during a total eclipse.