Origin: Latin suffix -al
Equinoctial has 5 different meanings across 2 categories:
the great circle on the celestial sphere midway between the celestial poles
The great circle midway between the celestial poles; the celestial equator.
relating to the vicinity of the equator
relating to an equinox (when the lengths of night and day are equal)
Of or relating to the spring or autumnal equinox.