great circle

/greɪt ˌsʌrkəl/

Other forms: great circles

Definitions of great circle

1. noun

   a circular line on the surface of a sphere formed by intersecting it with a plane passing through the center
   types:

   celestial equator, equinoctial, equinoctial circle, equinoctial line

   the great circle on the celestial sphere midway between the celestial poles

   ecliptic

   the great circle representing the apparent annual path of the sun; the plane of the Earth's orbit around the sun; makes an angle of about 23 degrees with the equator

   equator

   an imaginary line around the Earth forming the great circle that is equidistant from the north and south poles

   celestial horizon, horizon

   the great circle on the celestial sphere whose plane passes through the sensible horizon and the center of the Earth

   hour circle

   a great circle on the celestial sphere that passes through both celestial poles

   line of longitude, meridian

   an imaginary great circle on the surface of the earth passing through the north and south poles at right angles to the equator

   vertical circle

   a great circle on the celestial sphere passing through the zenith and perpendicular to the horizon

   observer's meridian

   a meridian that passes through the observer's zenith

   prime meridian

   meridian at zero degree longitude from which east and west are reckoned (usually the Greenwich longitude in England)

   magnetic meridian

   an imaginary line passing through both magnetic poles of the Earth

   type of:

   line

   a spatial location defined by a real or imaginary unidimensional extent