pertaining to an equinox, or the equinoxes, or to the time of equal day and night; as, the equinoctial line.-pertaining to the regions or climate of the equinoctial line or equator; in or near that line; as, equinoctial heat; an equinoctial sun.-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.-the equinoctial line.