Definitions
1.nounThe great circle midway between the celestial poles; the celestial equator.
2.nounThe terrestrial equator.
3.adjectiveOf or relating to the spring or autumnal equinox."an equinoctial gale or storm, i.e. one happening at or near the time of the equinox, in any part of the world"
4.adjectiveOf or relating to the celestial equator.
5.adjectiveEquatorial: Of or relating to the equator of the Earth.