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
Pertaining to an equinox, or the equinoxes, or to the time of equal day and night; as, the equinoctial line
{i} violent rainstorm at or near the time of the equinox; celestial equator, large circle surrounding the celestial sphere equidistant from the celestial poles
Pertaining to the regions or climate of the equinoctial line or equator; in or near that line; as, equinoctial heat; an equinoctial sun
{s} pertaining to a day characterized by equal period of daylight and night; pertaining of an instance in which the Sun crosses the Earth's equator; characteristic of regions near the Earth's equator
relating to an equinox (when the lengths or night and day are equal) relating to the vicinity of the equator