2. (Astron.) The great circle of the celestial sphere,
coincident with the plane of the earth's equator; -- so
called because when the sun is in it, the days and nights
are of equal length; hence called also the {equinoctial},
and on maps, globes, etc., the {equinoctial line}.
{Equator} {of the sun or of a planet} (Astron.), the great
circle whose plane passes through through the center of
the body, and is perpendicular to its axis of revolution.
{Magnetic equator}. See {Aclinic}.
2. Pertaining to the regions or climate of the equinoctial
line or equator; in or near that line; as, equinoctial
heat; an equinoctial sun.
3. 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.
{Equinoctial colure} (Astron.), the meridian passing through
the equinoctial points.
{Equinoctial line} (Astron.), the celestial equator; -- so
called because when the sun is on it, the nights and days
are of equal length in all parts of the world. See
{Equator}.
Thrice the equinoctial line He circled. --Milton.
{Equinoctial points} (Astron.), the two points where the
celestial and ecliptic intersect each other; the one being
in the first point of Aries, the other in the first point
of Libra.
{Equinoctial time} (Astron.) reckoned in any year from the
instant when the mean sun is at the mean vernal
equinoctial point.