1. (noun) September 22

• fall equinox
• september equinox

1. (noun) (astronomy) the equinoctial point that lies in the constellation of Virgo

• astronomy
• uranology

1. (noun) September 22

• equinox

2. (noun) (astronomy) the equinoctial point that lies in the constellation of Virgo

• equinoctial point
• equinox

1. (noun) September 22

• march equinox
• spring equinox
• vernal equinox