great circle

An aspect of the planets when they are distant from each other by twice the fifth part of a great circle -- that is, twice 72 degrees.

One of two great circles intersecting at right angles in the poles of the equator

the great circle representing the apparent annual path of the sun

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

(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)