(1):
(a.) 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.
(2):
(a.) Pertaining to the regions or climate of the equinoctial line or equator; in or near that line; as, equinoctial heat; an equinoctial sun.
(3):
(a.) Pertaining to an equinox, or the equinoxes, or to the time of equal day and night; as, the equinoctial line.
(4):
(n.) The equinoctial line.