great circle

great circle (plural great circles)

1. (geometry) A circle defined as the intersection of the surface of a sphere and a plane which passes through the centre of the sphere.
2. A segment of such circle representing the shortest distance between two points on the surface of a sphere.

   Synonym: great-circle arc

   • 1902, S. L. Penfield, “Use of the Stereographic Projection for Geographical Maps and Sailing Charts”, in American Journal of Science:

     Wherever a navigator may be, it certainly would be to his advantage to be able to find the great circle, or shortest course, and the distance, to his port of destination, [....]

   • 2003, Jeff Toghill, The Navigator's Handbook: Essential Methods and Equipment--and how to Use Them:

     The shortest distance between two points on an ocean Mercator chart is not a straight line - it is a curve known as a 'great circle'.

   • 2005, Phil Medina, Homework Helpers: Earth Science, page 52:

     Because the Earth's surface is curved, the shortest distance is actually a curve over the surface called a great circle.

• vertical circle

• great circle route

• small circle

•   great circle on Wikipedia.Wikipedia