An Etymological Dictionary of Astronomy and Astrophysics
English-French-Persian

Moving backward; having a backward motion or direction. → retrograde motion.

M.E., from L. retrogradus "going backward," from retrogradi "move backward," from retro- "backward" + gradi "to go, step."

Pasrow, pasraft, from pas- "back, behind," → back, + row, raft present and past stems of raftan "to go, walk;" (Mid.Pers. raftan, raw-, Proto-Iranian *rab/f- "to go; to attack").

The orbital motion or rotation of a solar system body in a clockwise direction (East to West) when viewed from the north pole of the ecliptic. It is a motion opposed to the → direct motion of the great majority of solar system bodies.

→ retrograde; → motion.

An object which has a retrograde orbit around its primary.

→ retrograde; → object.

An orbit with an inclination between 90° and 270° such as those of some comets and small asteroids orbiting the Sun.

→ retrograde; → orbit.