What is the shortest route between two points on a sphere called?

The term for the shortest route between two points on a sphere is known as a great circle route. This concept derives from the geometry of spheres, where a great circle is defined as the intersection of the sphere with a plane that passes through the center of the sphere. This means that great circle routes account for the curvature of the sphere, resulting in a path that is consistently the shortest distance compared to any other type of route, such as a direct or linear path across the surface.

The great circle route is commonly used in aviation and maritime navigation because it allows for efficiency in travel, reducing fuel consumption and travel time. In contrast, other terms like "direct route" and "linear path" do not accurately describe the shortest distance in a spherical context, and "circular route" implies a return to the starting point rather than a direct connection between two distinct points. Therefore, great circle routes are crucial for understanding navigation over large distances on Earth.