Emily Dickinson Lexicon

E-QUI-NOC'TIAL, a. [L. æquus, equal, and nox, night.]

1. Pertaining to the equinoxes; designating an equal length of 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; equinoctial wind.
3. Pertaining to the time when the sun enters the equinoctial points; as, an equinoctial gale or storm, which happens at or near the equinox, in any part of the world.
4. Equinoctial flowers, flowers that open at a regular stated hour. Martyn.