An elliptical orbit at a specific inclination, 60-odd degrees, usually with apogee above the Northern Hemisphere. The Earth's equatorial bulge normally causes the position of apogee and perigee to rotate in the plane of an elliptical orbit, but at the particular inclination of the Molniya orbits, this effect is zero and the apogee stays where its put. The Soviets use it for their Molniya communication satellites (whence the name) because it makes them more visible from very high latitudes than Clarke orbit. The inclination is high enough to miss the worst part of the inner Van Allen belt, which is near the equator.
