say it: EE-kwuh-nahks
equinox is a noun meaning "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". It carries 2 recorded senses.
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
(astronomy) either of the two celestial points at which the celestial equator intersects the ecliptic
astronomy
Forms marked · are formed by the regular rule rather than recorded in the source data. English keeps a few hundred irregulars and the rest follow the pattern, so the rule is right far more often than not — but it is a rule, and the mark says so.
Definitions, synonyms and semantic relations for equinox come from Princeton University’s WordNet. The pronunciation comes from the CMU Pronouncing Dictionary. Commonness is measured against a corpus of everyday English. Full sources and licences.