Definition that contains great circle
- horizon the great circle on the celestial sphere whose plane passes through the sensible horizon and the center of the Earth
- equator an imaginary line around the Earth forming the great circle that is equidistant from the north and south poles
- meridian an imaginary great circle on the surface of the earth passing through the north and south poles at right angles to the equator
- 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
- geodesic (mathematics) the shortest line between two points on a mathematically defined surface (as a straight line on a plane or an arc of a great circle on a sphere)
- equinoctial circle the great circle on the celestial sphere midway between the celestial poles
- spherical polygon a figure on the surface of a sphere bounded by arcs of 3 or more great circles
- line of longitude an imaginary great circle on the surface of the earth passing through the north and south poles at right angles to the equator
- equinoctial line the great circle on the celestial sphere midway between the celestial poles
- spherical triangle a spherical polygon formed by the arcs of 3 great circles