EQUINOCTIAL, in Geography. See EQUATOR.
The shadows of those who live under this circle are cast to the southward of them for one half of the year, and to the northward of them during the other half; and twice in a year, viz. at the equinoxes, the sun at noon casts no shadow, being in their zenith.
From this circle is the declination or latitude of places accounted in the degrees of the meridian.