equinox
nounUK /ˈiː.kwɪ.nɒks/
US /ˈiː.kwə.nɑːks/
An equinox is a day in spring or fall when daytime and nighttime are almost the same length.
The equinox happens twice a year, once in March and once in September.
OTHER MEANINGS
2. Either of the two points in the sky where the sun's path crosses the celestial equator.
Astronomers mark the equinox as the moment the sun passes the celestial equator.
3. A time of equal balance or a turning point between two opposite states.
The meeting felt like an equinox between the old plan and the new one.
4. One of the two dates each year when day and night are nearly equal everywhere on Earth.
Many cultures celebrate the spring equinox with festivals.