fall equinox vs equinox

fall equinox and equinox both are nouns.

Word	Noun	Adjective	Verb	Adverb
fall equinox	Yes	No	No	No
equinox	Yes	No	No	No

As nouns, equinox is a hypernym of fall equinox; that is, equinox is a word with a broader meaning than fall equinox:

fall equinox: September 22
equinox: either of two times of the year when the sun crosses the plane of the earth's equator and day and night are of equal length

fall equinox (noun)	equinox (noun)
September 22	(astronomy) either of the two celestial points at which the celestial equator intersects the ecliptic
	either of two times of the year when the sun crosses the plane of the earth's equator and day and night are of equal length