English

Noun

September equinox ‎(usually uncountable, plural September equinoxes)

1. (astronomy) The moment when the sun crosses the celestial equator while heading southward, occurring on September 22–23. That would be autumnal equinox in the northern hemisphere and vernal equinox in the southern hemisphere.

Synonyms

• southward equinox

Coordinate terms

• March equinox
• June solstice
• December solstice