from
The Collaborative International Dictionary of English v.0.48
Equinoctial \E`qui*noc"tial\, a. [L. aequinoctials, fr.
aequinoctium equinox: cf. F. ['e]quinoxial. See {Equinox}.]
1. Pertaining to an equinox, or the equinoxes, or to the time
of equal day and night; as, the equinoctial line.
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2. Pertaining to the regions or climate of the equinoctial
line or equator; in or near that line; as, equinoctial
heat; an equinoctial sun.
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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.
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{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}.
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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.
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