equinoctial definition

1. Pertaining to an equinox, or the equinoxes, or to the time of equal day and night; as, the equinoctial line.

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

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.

<astronomy> Equinoctial colure, 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. "Thrice the equinoctial line He circled.

<astronomy>" (Milton) - Equinoctial points reckoned in any year from the instant when the mean sun is at the mean vernal equinoctial point.

Origin: L. Aequinoctials, fr. Aequinoctium equinox: cf. F. Equinoxial. See Equinox.