The autumn equinox, also known as the fall equinox, is one of the two equinoxes that occur each year, the other being the spring equinox. It marks the point in the Earth’s orbit around the sun when the day and night are approximately of equal length, each lasting about 12 hours. The term “equinox” is derived from Latin, with “aequus” meaning “equal” and “nox” meaning “night,” signifying the equal duration of day and night during these periods.