An equinox happens twice a year when the sun crosses the plane
of the Earth's equator and day and night are of equal length.
the equinox is when the sun is directly above the equator
"Equi" comes from the word "equal"; "nox" means "night". So the "Equinox" means "equal nights", meaning that the length of the sunlit day is equal to the length of the night. This occurs when the Sun is directly over the equator.
This happens twice each year, around March 21 and September 21.
(These dates can vary a day either way, depending on the cycle of
They are the two times during the year, one in March and the other in September, when the sun passes directly over the equator. At these times periods of daylight and night time are of virtually the same length all over the globe, except for very near the poles.