noun me·rid·i·an \mə-ˈri-dē-ən\

: any one of the lines that go from the North Pole to the South Pole on maps of the world

Full Definition of MERIDIAN

archaic :  the hour of noon :  midday
:  a great circle of the celestial sphere passing through its poles and the zenith of a given place — see azimuth illustration
:  a high point
a (1) :  a great circle on the surface of the earth passing through the poles (2) :  the half of such a circle included between the poles
b :  a representation of such a circle or half circle numbered for longitude on a map or globe — see longitude illustration
:  any of the pathways along which the body's vital energy flows according to the theory behind acupuncture
meridian adjective

Examples of MERIDIAN

  1. <a lawyer at the meridian of his career arguing a case before the U.S. Supreme Court>

Origin of MERIDIAN

Middle English, from Anglo-French meridien, from meridien of noon, from Latin meridianus, from meridies noon, south, irregular from medius mid + dies day — more at mid, deity
First Known Use: 14th century

Other Astronomy Terms

gibbous, nadir, nebulous, penumbra, retrograde, sidereal, syzygy, wane, wax, zenith


geographical name Me·rid·i·an \mə-ˈri-dē-ən\

Definition of MERIDIAN

city SW Idaho W of Boise pop 75,092
city E cen Mississippi pop 41,148
MERIDIAN Defined for Kids


noun me·rid·i·an \mə-ˈri-dē-ən\

Definition of MERIDIAN for Kids

:  any imaginary semicircle on the earth's surface reaching from the north pole to the south pole
:  a representation of a meridian on a map or globe numbered according to degrees of longitude
Medical Dictionary


noun me·rid·i·an \mə-ˈrid-ē-ən\

Medical Definition of MERIDIAN

:  an imaginary circle or closed curve on the surface of a sphere or globe-shaped body (as the eyeball) that lies in a plane passing through the poles
:  any of the pathways along which the body's vital energy flows according to the theory of acupuncture
meridian adjective
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