Equinoccial

Part of speech: adjective

Definitions

1. Relating to or characteristic of an equinox, the time when day and night are equal length ; happening at or near the time of an equinox
2. Of or pertaining to an equinox and the equal division of day and night ; taking place at or around the season of an equinox
3. Connected with an equinox when the sun crosses the celestial equator ; occurring during or around the equinoctial period

Etymology: Its roots are two Latin words, "aequus," meaning "equal," and "nox," meaning "night." The Latin noun "aequinoctium" named the moment when day and night are roughly equal in length, and the adjective formed from it described anything relating to that moment. English took the adjective from Old French and Medieval Latin, and it has been used in English for centuries. In astronomy the adjective survives in "equinoctial line," the name for the celestial equator, the great circle the sun crosses at the equinoxes. The spelling with double "c" is a variant of the more common "equinoctial," and it is the same word.

Synonyms: equinoctial, autumnal, vernal

Antonyms: solsticial