Orthodromic

Part of speech: adjective

Definitions

1. Describing the shortest distance along the surface of a sphere between two locations, it pertains to the most efficient path in a curved context and is associated with geodesic measurement in spherical geometry
2. This term indicates the minimal distance connecting two points across a spherical surface, emphasizing the optimal route on a curved plane, and is tied to the principles of geodesics
3. Referring to the route that connects two points along a sphere's surface, following the shortest possible distance between them

Etymology: Ancient Greek gave us "orthos" (straight, correct) and "dromos" (a course or race track, from the verb "trechein", to run). Put together, "orthodromos" meant something like "running straight," and it was used in navigation for the shortest route between two points on a curved surface. The adjective "orthodromic" is a modern scientific formation: English took "ortho-" from Greek and attached "-ic," a suffix inherited through Latin "-icus" and Old French "-ique." The word's sense is geometric rather than everyday. On a sphere such as the Earth, a straight line on a flat map is not the shortest path; the shortest route follows a great circle, the arc cut by a plane through the centre of the sphere. Navigators and pilots call this an orthodromic course, and it is what gives long-haul flight paths their curving look on a flat chart.