Word origin · etymology
Traditional descriptive geometric phrase.
Great identifies the largest circle cut from a sphere: its plane passes through the sphere's center.
How we know · epistemology
Spherical geometry
On a sphere, a great circle follows a plane through the center and can extend a chosen local direction. Antipodal points leave the route ambiguous without a bearing; the model also approximates Earth's actual ellipsoidal surface.
Connected concepts
Browse other concepts in Maps & directions →
These links connect subjects and terminology. They do not establish a shared historical origin.
Sources & provenance
Use the citations beside each section to distinguish a calculation convention, a historical teaching and an editorial example.