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

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory

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<< < -es -iv -ti 21- A r abe abs abs acc acc acc act act ada adi adu aff age alc Alf ali all alp alt ama amp ana ang ang ann ano ant ant ape apo app aps arc Arg ari art ass ast ast ast atm ato att aur aut axi B r bac Bal Bar Bar Bay bec Ber Bet Bie bij bin bio bis bla bla blu blu bol Bor bou Bra bre bro Bug C-s cal Cam can car Car Cas cat cav cel cen cer Cha cha cha che cho cir cir cir cla clo clo clu coa coe coh col col col com com com com com com com com com con con con con con con con con con con con coo cor cor cor cos cos cos Cou cou Cra Cre cri cro cub cur cyc cyl dar dat daw de- Deb dec dec dee def deg del Den dep der det deu dew dic dif dif dil dip dir dis dis dis dis dis div dog Dop dou dra dua dus dwa dyn e-m ear ecl eco eff ein Ein elb ele ele ele ele Els emi emp ene enr env epi equ equ Eri est Euc eva evo exc exc exh exo exp exp ext ext f-n Fah fam fau fee Fer fib fil fin fir fix fle flu foc for for for fra fre fre fri fun fuz gal gal gal Gan gau GCN gen geo geo geo geo Gl glo gra gra gra gra gra gre gro GW1 hab hal han HAR haz hea hel hel Hen Her heu Hig Hil hol hop hor hou Hub Hum Hyd hyd hyd hyp hys ide ign ima imp imp inc inc ind ine inf inf inf inh INP ins ins int int int int Int int int int inv ion iri irr iso iso iso Jea Jos Jun K2 Kep key kin Kol lag lam Lan lar las lav lea leg len lev lig lim lin lin lin lis lob loc log lor low lum lun lun Lym Mac mag mag mag mag mag mai Mal mar mas mas mat max mea mea mee Men mer met met met mic mid Mil min Mir mix mod mod mol mon Mor mou mul muo mys nan nat nav nec Nep neu New New NGC nob nom non non nor not nuc nuc num Nyq obj obs obs oce oen OH omn opa ope opt opt opt orb ord Ori ort osc out ove oxy pal pan par Par par par pas pea Pen per per per per per pet pha pho pho pho phy pie Pit Pla pla pla pla ple Poi pol pol pol pol pop pos pos pow pre pre pre Pre pri pri pri pro pro pro pro pro pro Pro pub pul pyr qua qua qua qua Qui rad rad rad rad rad rad ram ran rat rea rec rec rec red ref ref reg reg rel rel rem rep res res res ret rev rho Rie rim riv rol Ros rot rul S a Sah san Sat sca Sch Sch scr sec sec sec sei sel sem sep set sha she sho sid sig sil sim sin sit sky slu sno sof sol sol sol sol sou sou spa spa spe spe spe sph spi spl spr sta sta sta sta sta ste ste sti sto str str sub sub sub sug sun sup sup sup sup sur syl syn sys tal Tay tel ten ter tex the the the thi tho thu tid tim tod top tot tra tra tra tra tri tri tro tru tur twi Typ UFO ult unc uni uni uni upg ura uti val var vec vel ver ver vig vir vis voc von wak Was wav wax wea wei whi Wie win WN6 wom X-r yel you zer zod > >>

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ratio
  وابَر   
vâbar

Fr.: rapport   

Math.: The quotient of two quantities arrived at by dividing one by the other.

From L. ratio "reckoning, calculation," also "reason," from rat-, p.p. stem of reri "to reckon, calculate," also "think," → reason.
Fr. rapport, back-formation from rapporter "bring back," from → re- "back, again" + apporter "to bring," from L. apportare "to bring," from → ad- "to" + portare "to carry."

Vâbar, on the model of Fr. rapport "bringing back," as above, from vâ- prefix meaning "back to the original place, again," → re-, + bar present stem of bordan "to carry, lead" (Mid.Pers. burdan, O.Pers./Av. bar- "to bear, carry," barəθre "to bear (infinitive)," Skt. bharati "he carries," Gk. pherein, L. fero "to carry;" PIE base *bher- "to carry").

rational
  ۱) راینی، راینوار؛ ۲) خردانه، خردمندانه؛ ۳) وابری   
1) râyani, râyanvâr; 2) xeradâné, xeradmandâné; 3) vâbari

Fr.: rationnel   

1) Having or exercising the ability to → reason.
2) Consistent with or based on reason; logical; in accordance with sound reasoning.
3) Math.: Capable of being expressed as a quotient of integers.

M.E. racional, from O.Fr. racionel, from L. rationalis "of or belonging to reason, reasonable," from ratio (genitive rationis) "reckoning, calculation, reason," from rat-, pp. stem of reri "to reckon, calculate; consider, think."

1) Râyani, of or pertaining to râyan, → reason.
2) Xeradâné, xeradmandâné, of or pertaining to xerad "understanding, judgement, intellect, wisdom;" Mid.Pers. xrad "reason, intellect, intelligence, wisdom, understanding;" O.Pers. xraθu- "wisdom;" Av. xratu- "intelligence, undestanding, wisdom; will, purpose, council;" cf. Skt. krátu- "power, will-power;" Gk. kratos "power, strength."
3) vâbari, of or pertaining to vâbar, → ratio.

rational number
  عدد ِ وابری   
'adad-e vâbari

Fr.: nombre rationnel   

Any number that can be expressed as a ratio of two integers, providing the second number is not zero.

rational; → number.

rationale
  راینال   
râyanal

Fr.: raisonnement, exposé raisonné   

1) The fundamental reason or reasons serving to account for something.
2) A statement of reasons.
3) A reasoned exposition of principles (Dictionary.com).

L. neuter of rationalis.

Râyanâl, from râyan, → reason, + -âl, → -al.

rationalism
  راین‌باوری، خردباوری   
râyan-bâvari, xerad-bâvari

Fr.: rationalisme   

A philosophical doctrine that holds that → reason alone, unaided by experience, can arrive at basic truth regarding the world.

From → rational + -ism a Gk. suffix used in the formation of nouns denoting action or practice, state or condition, principles, doctrines, and so forth.

Râyan, → reason; xerad, → rational; bâvari, from bâvar "belief" (Mid.Pers. wâbar "beleif;" Proto-Iranian *uar- "to choose; to convince; to believe;" cf. Av. var- "to choose; to convince" varəna-, varana- "conviction, faith;" O.Pers. v(a)r- "to choose; to convince;" Skt. vr- "to choose," vara- "choosing").

raven
  کلاغ   
kalâq (#)

Fr.: corbeau   

Any of several large, corvine birds having lustrous, black plumage and a loud, harsh call, especially Corvus corax, of the New and Old Worlds (Dictionary.com).

O.E. hræfn, hrefn; hræfn, cognate with O.Norse hrafn, Dan. ravn, Du. raaf, Ger. Rabe "raven," ultimately from PIE root *ker- imitative of harsh sounds (source also of L. crepare "to creak, clatter," cornix "crow," corvus "raven;" Gk. korax "raven," korone "crow;" O.C.S. kruku "raven;" Lith. krauklys "crow," related to Pers. kalâq, as below.

Kalâq, ultimately from Proto-Iranian*karak-, from *kar- "raven's harsh sound;" cf. Pers. qâr, qârqâr "croak," cognate with L. corvus, Gk. korax "a raven," Skt. kâkah, E. raven, as above and → crow.

raw data
  داده‌های ِ خام   
dâdehâ-ye xâm

Fr.: données brutes   

Data that are unprocessed or not yet subjected to analysis.

Raw, from M.E., from O.E. hreaw "uncooked, raw;" cf. M.Du. rau, O.H.G. hrawer, Ger. roh; PIE base *krowos "congealed, bloody" cf. Skt. kravis- "raw flesh," krura- "bloody, raw, hard;" Gk. kreas "flesh;" L. crudus "not cooked," cruor "thick blood;" Lith. kraujas, O.C.S. kruvi "blood;" → data.

Dâdehâdata; xâm "crude, uncooked;" Mid.Pers. xâm "crude, raw" (Khotanese hāma- "raw;" Ossetic xom "raw;" Pash. ôm "raw"); cf. Skt āmá- "raw, uncooked;" Gk. omos "raw, uncooked."

ray
  پرتو   
partow (#)

Fr.: rayon   

1) Any of the lines or streams in which light appears to radiate from a luminous body. → light ray.
2) The straight line normal to the wave front in the propagation of radiant energy.
3) A stream of material particles all moving in the same straight line.

M.E. raie, raye, from O.Fr. rai "ray, spoke," from L. → radius "ray, spoke, staff, rod."

Partow, ultimately from Proto-Iranian *pari-tap- "to shine around, radiate away." The first component *pari- "around, about;" cf. Mod.Pers. par-, pirâ- "around, about," from Mid.Pers. pêrâ; O.Pers. pariy "around, about," Av. pairi "around, over," per- "to pass over, beyond;" Skt. pari; Gk. peri "around, about, beyond;" L. per "through;" PIE base *per- "through, across, beyond." The second component *tap- "to shine, radiate;" cf. Mod.Pers. tâbidan, variants tâftan "to shine," tafsidan "to become hot;" Mid.Pers. tâftan "to heat, burn, shine;" taftan "to become hot;" Parthian t'b "to shine;" Av. tāp-, taf- "to warm up, heat," tafsat "became hot," tāpaiieiti "to create warmth;" cf. Skt. tap- "; to heat, be/become hot; to spoil, injure, damage; to suffer," tapati "burns;" L. tepere "to be warm," tepidus "warm;" PIE base *tep- "to be warm."

ray of class 1
  پرتو ِ رده‌ی ِ ۱   
partw-e rade-ye 1

Fr.: rayon de classe 1   

In → rainbows, a sun ray directly reflected from the surface of a water → droplet.

ray; → class.

ray of class 2
  پرتو ِ رده‌ی ِ ۲   
partw-e rade-ye 2

Fr.: rayon de classe 2   

In → rainbows, a sun ray transmitted directly through a water → droplet.

ray; → class.

ray of class 3
  پرتو ِ رده‌ی ِ ۳   
partw-e rade-ye 3

Fr.: rayon de classe 3   

In → rainbows, a sun ray that emerges from a water → droplet after one internal reflection. Rays of class 3 give rise to the → primary rainbow.

ray; → class.

ray of class 4
  پرتو ِ رده‌ی ِ ۳   
partw-e rade-ye 4

Fr.: rayon de classe 4   

In → rainbows, a sun ray that emerges from a water → droplet after two internal reflections. Rays of class 4 give rise to the → secondary rainbow.

ray; → class.

rayleigh
  ریلی   
rayleigh (#)

Fr.: rayleigh   

A c.g.s. unit of light intensity used in astronomy and physics to measure the brightness of the night sky, auroras, etc. One rayleigh (R) represents the light intensity of one million photons of light emitted in all directions per square centimeter of receiver per second; or, in SI units, 795.775 x 106 photons per square meter per steradian (m-2·sr-1). A dark night sky has a light intensity of roughly 250 R.

In honor of the English mathematician and physicist Lord Rayleigh (1842-1919), surname of John William Strutt, Third Baron Rayleigh, whose research ranged over several fields of physics.

Rayleigh line
  خط ریلی   
xatt-e Rayleigh

Fr.: 1) droite de Rayleigh; 2) raie de Rayleigh   

1) A straight line that connects the points corresponding to the initial and final states on a graph of pressure versus specific volume for a substance subjected to a → shock wave. The slope of the Rayleigh line is proportional to the square of shock speed. Steeper Rayleigh lines correspond to higher shock speeds. See also → Hugoniot curve.
2) In → Raman scattering, the spectral line in scattered radiation which has the same frequency as the corresponding incident monochromatic radiation.

rayleigh; → line.

Rayleigh number (Ra)
  عدد ِ ریلی   
adad-e Rayleigh

Fr.: nombre de Rayleigh   

The ratio of the buoyancy force to the viscous force in a medium. This dimensionless number is used to estimate when convection commences in a fluid. It depends on the density and depth of the fluid, the coefficient of thermal expansion, the gravitational field, the temperature gradient, the thermal diffusivity, and the kinematic viscosity. Convection usually starts when Ra is 1000 or more, while heat transfer is entirely by conduction when Ra is less than 10.

rayleigh; → number.

Rayleigh scattering
  پراکنش ِ ریلی   
parâkaneš-e Rayleigh

Fr.: diffusion Rayleigh   

The scattering of light by → particles of size small compared with the → wavelength of light. The intensity of the light scattered by unit volume of the medium at an angle θ to the direction of propagation of the incident light is: Iθ = 8 π4α2 N I0 (1 + cos2θ)/(R2λ4), where α is the → molecular polarizability, N is the number of scattering molecules, I0 is intensity of the incident light, λ is the wavelength, and R is the distance from the scatterer. The fourth power dependence on wavelength means that blue light is much more strongly scattered than red light from a medium containing very fine particles. The air molecules, mostly → nitrogen (78%) and → oxygen (21%) are some 1,000 times larger than → visible light wavelengths. This accounts for the bluish appearance of smoke and of clear sky when the observation is not along the direction of illumination. The setting Sun, seen through a considerable thickness of atmosphere appears reddish because long wave radiation predominates in the transmitted light.
Historically, John Tyndall first discovered this phenomenon in 1859 (→ Tyndall effect), but Lord Rayleigh studied it in more detail in 1871.

rayleigh; → scattering.

Rayleigh's criterion
  سنجیدار ِ ریلی   
sanjidâr-e Rayleigh

Fr.: critère de Rayleigh   

A criterion for the instability of a basic swirling flow with an arbitrary dependence of angular velocity Ω(r) on the distance r from the axis of rotation. This states that in → inviscid fluids: Ω(r) < 0 for instability, where Ω = (1/r3) (d/dr)(r4Ω4).

Rayleigh; → criterion.

Rayleigh-Jeans law
  قانون ِ ریلی-جینز   
qânun-e Rayleigh-Jeans(#)

Fr.: loi de Rayleigh-Jeans   

A classical law approximately describing the intensity of radiation emitted by a → blackbody. It states that this intensity is proportional to the temperature divided by the fourth power of the wavelength (8πkT4). The Rayleigh-Jeans law is a good approximation to the experimentally verified Planck radiation formula only at long wavelengths. At short wavelengths it runs into a paradox named the → ultraviolet catastrophe.

Rayleigh; → Jeans; → law.

Rayleigh-Jeans spectrum
  بیناب ِ ریلی-جینز   
binâb-e Rayleigh-Jeans

Fr.: spectre Rayleigh-Jeans   

The part of → electromagnetic spectrum approximated by the → Rayleigh-Jeans law.

Rayleigh; → Jeans; → spectrum.

Rayleigh-Taylor instability
  ناپایداری ِ ریلی-تیلر   
nâpâydâri-ye Rayleigh-Taylor

Fr.: instabilité Rayleigh-Taylor   

A type of hydrodynamical instability between two fluids of different densities, which occurs when the heavy fluid lies above the lighter fluid in a gravitational field. More generally a material interface is said to be Rayleigh-Taylor unstable whenever the fluid acceleration has an opposite direction to the density gradient.

rayleigh; → Taylor number; → instability.

<< < -es -iv -ti 21- A r abe abs abs acc acc acc act act ada adi adu aff age alc Alf ali all alp alt ama amp ana ang ang ann ano ant ant ape apo app aps arc Arg ari art ass ast ast ast atm ato att aur aut axi B r bac Bal Bar Bar Bay bec Ber Bet Bie bij bin bio bis bla bla blu blu bol Bor bou Bra bre bro Bug C-s cal Cam can car Car Cas cat cav cel cen cer Cha cha cha che cho cir cir cir cla clo clo clu coa coe coh col col col com com com com com com com com com con con con con con con con con con con con coo cor cor cor cos cos cos Cou cou Cra Cre cri cro cub cur cyc cyl dar dat daw de- Deb dec dec dee def deg del Den dep der det deu dew dic dif dif dil dip dir dis dis dis dis dis div dog Dop dou dra dua dus dwa dyn e-m ear ecl eco eff ein Ein elb ele ele ele ele Els emi emp ene enr env epi equ equ Eri est Euc eva evo exc exc exh exo exp exp ext ext f-n Fah fam fau fee Fer fib fil fin fir fix fle flu foc for for for fra fre fre fri fun fuz gal gal gal Gan gau GCN gen geo geo geo geo Gl glo gra gra gra gra gra gre gro GW1 hab hal han HAR haz hea hel hel Hen Her heu Hig Hil hol hop hor hou Hub Hum Hyd hyd hyd hyp hys ide ign ima imp imp inc inc ind ine inf inf inf inh INP ins ins int int int int Int int int int inv ion iri irr iso iso iso Jea Jos Jun K2 Kep key kin Kol lag lam Lan lar las lav lea leg len lev lig lim lin lin lin lis lob loc log lor low lum lun lun Lym Mac mag mag mag mag mag mai Mal mar mas mas mat max mea mea mee Men mer met met met mic mid Mil min Mir mix mod mod mol mon Mor mou mul muo mys nan nat nav nec Nep neu New New NGC nob nom non non nor not nuc nuc num Nyq obj obs obs oce oen OH omn opa ope opt opt opt orb ord Ori ort osc out ove oxy pal pan par Par par par pas pea Pen per per per per per pet pha pho pho pho phy pie Pit Pla pla pla pla ple Poi pol pol pol pol pop pos pos pow pre pre pre Pre pri pri pri pro pro pro pro pro pro Pro pub pul pyr qua qua qua qua Qui rad rad rad rad rad rad ram ran rat rea rec rec rec red ref ref reg reg rel rel rem rep res res res ret rev rho Rie rim riv rol Ros rot rul S a Sah san Sat sca Sch Sch scr sec sec sec sei sel sem sep set sha she sho sid sig sil sim sin sit sky slu sno sof sol sol sol sol sou sou spa spa spe spe spe sph spi spl spr sta sta sta sta sta ste ste sti sto str str sub sub sub sug sun sup sup sup sup sur syl syn sys tal Tay tel ten ter tex the the the thi tho thu tid tim tod top tot tra tra tra tra tri tri tro tru tur twi Typ UFO ult unc uni uni uni upg ura uti val var vec vel ver ver vig vir vis voc von wak Was wav wax wea wei whi Wie win WN6 wom X-r yel you zer zod > >>