Explanation

"Equinox"  means Equal duration of day and night.

The time or date (twice each year) at which the sun crosses the celestial equator  when day and night are of approximately equal length.

During the equinoxes, solar declination is 0°

the September equinox is called the autumnal or fall equinox on 23 September

the March equinox is called the vernal or spring equinox on 19 March or as late as 21 March

ND-8-08-2023