1. Either of the two times each year when day and night are approximately equal in length, occurring around March 20 and September 22.
Usage: Plural of equinox; The vernal (spring) equinox occurs in March; the autumnal equinox occurs in September in the Northern Hemisphere

Examples

• The two equinoxes divide the year into seasons of roughly equal daylight and darkness.
• During the equinoxes, the sun is directly above the equator.
• Spring and fall equinoxes mark important transitions in the calendar.
• Many cultures celebrate the equinoxes as significant astronomical events.
• The equinoxes occur at different dates each year due to Earth's orbital mechanics.
• Students learn about equinoxes and solstices in their astronomy classes.