01 n. The imaginary great circle on the earth's surface, everywhere equally distant from the two poles, and dividing the earth's surface into two…
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1.
The imaginary great circle on the earth's surface, everywhere equally distant from the two poles, and dividing the earth's surface into two hemispheres.(Geog.)
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2.
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.(Astron.) Also: equinoctial, equinoctial line
Phrases & compounds
Equator of the sun —
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.