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

A suffix forming agent nouns, occurring originally in loanwords from Anglo-French; it now functions in E. as an orthographic variant of -er.

From M.E., from O.Fr. -o(u)r, from L. or-, extracted from -tor; Gk. -tor (e.g. dotor "giver," genetor "begetter," ktistor "founder"); cf. Av. -tar- (dātar- "giver," astar- "thrower," baxtar- "tributor"); Skt. -tr- (kartr- "doer," dhātr- "founder," astr- "thrower").

Agent suffix -gar, variant -gâr, -kâr, from kar-, kardan "to do, to make" (Mid.Pers. kardan; O.Pers./Av. kar- "to do, make, build;" Av. kərənaoiti "makes;" cf. Skt. kr- "to do, to make;" krnoti "makes," karma "act, deed;" PIE base k^wer- "to do, to make"). Suffix -âr, as in parastâr, xaridâr, foruxtâr, virâstâr, xâstâr, nemudâr. Agent suffix -andé, used with verbs.

Of or relating to two or more celestial bodies that share, or almost share, the same orbit.

→ co-; → orbital.

The motion of two or more bodies around the Sun on different orbits when it takes them the same amount of time to complete one revolution. There are three possible types of co-orbital motions of a small body associated with a planet: → tadpole orbits, → horseshoe orbits, and → quasi-satellite orbits.

→ co-orbital; → motion.

Any of satellites which either share the same orbit or which occupy immediately adjacent orbits that change periodically as the satellites approach one another (Ellis et al., 2007, Planetary Ring Systems, Springer).

→ co-orbital; → satellite.

The action or quality of a → co-orbiting asteroid.

From co- "together," → com- + → orbit + → -ing.

From ham- "together," → com- + madâr→ orbit + -i noun suffix.

An asteroid having a → co-orbital motion.

→ co-orbiting; → asteroid.

To cause a spacecraft to leave its operational orbit to enter a descent phase or to change course.

From → de- + → orbit.

Of a spacecraft, the act or process of departing from an operational orbit. → de-orbit.

Noun form of → de-orbit.

A → differential equation containing only the first → derivative. For example, dy/dx = 3x and 2y(dy/dx) + 3x = 5.

→ first; → order; → differential; → equation.

A system of → formal logic that is an extension of → propositional logic. It is also known as → first-order predicate calculus and → predicate logic. FOL eliminates deficiencies of propositional logic by: representing → objects (their properties, relations and statements about them), introducing → variables, and introducing → quantifiers.

→ first; → order; → predicate; → logic.

For a → function with several → variables, the derivative, done only once, with respect to one of the variables. For example ∂u/∂x for u = u(x,y).

→ first; → order; → partial; → derivative.

Same as → first-order logic.

→ first; → order; → predicate; → calculus.

An optical spectrum, produced by a diffraction grating, in which the difference in path length of light from adjacent slits is one wavelength.

→ first; → order; → spectrum.

In computer science a programming technique that uses → objects and their interactions to design applications and programs.

→ object; oriented, p.p. from the verb of → orientation; → programming.

Barnâme-sâzi, → programming; barâxt, → object; gerâ agent adj. of gerâyidan "to incline toward; to intend; to make for." The stem gerâ may be a variant of Mod.Pers. kil "bent, inclined" (k/g and l/r interchanges), from PIE base *klei- "to lean, incline," cognate with L. clinare "to bend" (E. declination, inclination, etc.), Gk. klinein "to cause to slope, slant, incline," Skt. sri- "to lean," O.Pers. θray-, Av. sray- "to lean," P.Gmc. *khlinen (Ger. lehnen, E. lean).

An n extension of → first-order logic that quantifies not only → variables that range over → individuals, but also quantifies over → relations.

→ second; → order; → predicate; → logic.

1) Astro.: A relationship between the orbital period of one body around another and its rotational period on its axis. The relationship results from tidal forces between the two bodies. For example, the rotation period of the Moon equals its revolution period around the Earth.
2) Quantum mechanics: The interaction between a particle's → spin angular momentum and its → orbital angular momentum.

→ spin; → orbit; → coupling.

A set in which every → nonempty → subset has a minimum element.

→ well; → order; → set.