word means "equal night." It refers to the two moments each
year when the sun appears to cross the equator. The spring (vernal)
equinox is around March 21 and the fall (autumnal) equinox is around
September 23. Everywhere on earth has about 12 hours of daylight and
12 hours of night on the equinoxes.
The sun doesn't really move, but it looks like it does to
us. That's because our Earth is tilted as it revolves around the sun
once a year.