equinoctial

a. [ L. aequinoctials, fr. aequinoctium equinox: cf. F. équinoxial. See Equinox. ] 1. Pertaining to an equinox, or the equinoxes, or to the time of equal day and night; as, the equinoctial line. [ 1913 Webster ]

2. Pertaining to the regions or climate of the equinoctial line or equator; in or near that line; as, equinoctial heat; an equinoctial sun. [ 1913 Webster ]

3. Pertaining to the time when the sun enters the equinoctial points; as, an equinoctial gale or storm, that is, one happening at or near the time of the equinox, in any part of the world. [ 1913 Webster ]

Equinoctial colure (Astron.), the meridian passing through the equinoctial points. --
Equinoctial line (Astron.), the celestial equator; -- so called because when the sun is on it, the nights and days are of equal length in all parts of the world. See Equator. [ 1913 Webster ] Thrice the equinoctial line
He circled. Milton. --
Equinoctial points (Astron.), the two points where the celestial and ecliptic intersect each other; the one being in the first point of Aries, the other in the first point of Libra. --
Equinoctial time (Astron.) reckoned in any year from the instant when the mean sun is at the mean vernal equinoctial point. [ 1913 Webster ]