great circle – Any circle on the surface of a sphere that lies on a plane through its center, or a circle that divides into two equal parts—as the Equator. More…
quadrant – A quarter of a circle or sphere. More…
rhumb line – A line on a sphere that cuts all meridians at the same angle; the path taken by a ship or plane that maintains a constant compass direction. More…
diameter – From Greek, meaning “measure through” (a circle or sphere, etc.). More…