equinox
Pronunciation:
/ˈiːkwɪˌnɒks//ˈiːkwəˌnɑːks/noun
Definitions
The intersection of the apparent path of the sun in the sky (the ecliptic) with the celestial equator.
One of the two days on which this intersection occurs each year: (for the Northern hemisphere) March 20 or 21 in the spring and September 22 or 23 in the autumn.