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

1) To lower in dignity or estimation; bring into contempt.
2) To lower in character or quality; debase.
3) Chemistry: Of a compound, especially an organic hydrocarbon, to break down (Dictionary.com).

→ de-; → grade.

1) A downward slope, especially of a road.
2) To assign to a lower status; to minimize the importance of (Dictionary.com).

→ down; → grade.

1) A degree or step in a scale, as of rank, advancement, quality, value, or intensity.
2) To arrange in a series of grades; class; sort (Dictionary.com).

From Fr. grade "grade, degree," from L. gradus "step, pace, gait, walk;" figuratively "a step, stage, degree," related to gradi "to walk, step, go," and second element in congress, progress, etc.; from PIE *ghredh-; cf. Lith. gridiju "to go, wander," O.C.S. gredo "to come," O.Ir. in-greinn "he pursues."

Padâk, from Baluci padâk "step, stair, ladder" (ultimately from Proto-Ir. *padaka-), older form of Pers. pâyé "step, base," from Mid.Pers. pâd, pây; Av. pad-, cf. Skt. pat: Gk. pos, genitive podos; L. pes; PIE *pod-/*ped-.

A rotational or orbital movement that is the same as most bodies within a celestial system. In the solar system, the apparent eastward motion of a celestial body on the celestial sphere. Opposed to → retrograde motion. Same as → direct motion.

From → pro- "forward" + grade, from L. gradi "to go, step, walk;" → motion.

Jonbeš, → motion; farârow, from farâ- "forward," → pro-, + row present stem of raftan "to go, walk;" Mid.Pers. raftan, raw-, Proto-Iranian *rab/f- "to go; to attack."

Same as →prograde motion.

→ prograde motion; → orbit.

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.

1a) An incline going up in the direction of movement.
1b) An increase or improvement.
1c) A new version, improved model, etc.
2a) To promote to a higher grade or rank.
2b) To improve or enhance the quality or value of (Dictionary.com).

→ up; → grade.