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

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory

   Homepage   
   


A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

<< < -es -iv -ti 21- a p abe abs abs acc acc acc act act ada adi ads aes Age Alb Alf ali all alp alt ama amp ana ang ang ann ano ant ant ape apo app app arc Arg ari art ass ast ast ast atm ato att Aur aut axi azi bac Bal Bar Bar Bay Bec Ber bet bic bij bin bio Bir bla Bla blu blu bol Boo bou bra Bre bro bug C r cal Cal can car Car Cas cat cau cel cen cer Cha cha Cha che chl cir cir cir Cla cli clo clu co- coc coh col col col com com com com com com com com Com con con con con con con con con con con con con Cop Cor cor cor cos cos Cou cou cow cre cri cro cry cur cut Cyg dam dar dat de deb dec dec ded def deg del dem den dep des det dev dia dif dif dig dio Dir dis dis dis dis dis dis div don dou dow dro dur dwa dyn Dys ear ebb ecl edg egg Ein Ela ele ele ele ele ell eme emp enc eng ent epi equ equ Equ esc eth Eur eve exa exc exe exi exp exp ext ext eye fac fal Far fed fer fer fie fin fir fit fla flo flu fol for for Fou fra fre Fre fro fuz gai Gal Gal gam gas Gau gen gen geo geo geo gia glo gol gra gra gra gra gre gri gui H I hai Ham har Hau hea hec hel hel her HES hie hig his hom hor hot Hub hum Huy hyd hyd hyl hyp ice ide ima imp imp imp inc ind ind ine inf inf inf ini ins ins ins int int int int Int int int int inv ion iro irr iso iso ite jel Jou Jup kao Kep kil Kip Kra Lag Lam lan lar las law lea leg Leo lex lig lim lin lin lin lit Loc loc log Lor low lum lun lun Lym mac mag mag mag mag mag mai Mal mar mas mas mat max mea mec meg men mer met met met mic mic Mik min min mis mob mod mol mon moo mou mul mul mys nan Nat nau nec neo neu nev New NGC no nom non non nor not nuc nuc num nut obj obs obs occ odd OH Ome Oor ope opp opt opt orb ord ori ort osc out ove oxi pai Pan par par par par pas pea pen per per per per Per per pha phl pho pho pho pi pip Pla pla pla pla ple poa pol Pol pol pol pop pos pos pot pra pre pre pre pri pri pri pro pro pro pro pro pro pro Pto pul puz qua qua qua qua qui rad rad rad rad rad rad rai ran rar Ray rea Rea rec rec red red ref ref reg rel rel rel rep res res res res ret Rhe rid rig ris Roe Ros rot rub rut Sag sam sat sca sca Sch sci sea sec sec see sel sem sen ser Sh2 sha shi sho sid sig sim sin Sir ske sli Smo soc sol sol sol sol sol sou spa spa spe spe spe spe sph spi spo Squ sta sta sta sta ste ste ste sto str str str sub sub sub sum sup sup sup sup sur sus sym syn T d tap tec tem ten tes the the the the thi thr tid tim tip ton tor tow tra tra tra tra tri tri tru tub tur two Typ ult un- und uni uni unp upp urg V20 Van var veg vel ver vib vio vir vis Vol Vul wan wat wav WC4 wea wel whi Wil wis WNL wor X-r Yer Z s zer [C > >>

Number of Results: 12982 Search : far
fine dust
  ریزگرد، غبار ِ نازک   
rizgard, qobâr-e nâzok

Fr.: poussière fine   

Meteorology: An → inhomogeneous  → mixture of tiny, part → solid, part → liquid or → gaseous  → particles that are, in average, smaller than ten → microns. The constituents are soot, heavy metals, organic substances, and dioxins. The smaller these dust particles, the deeper they penetrate into the lung. Larger particles are intercepted by mucous membrane in nose, mouth, and throat but smaller particles can penetrate the smallest lung bronchioles and may cause severe damage (various respiratory disorders, lung cancer) → particulate matter.

fine; → dust.

fine structure
  ساختار ِ نازک   
sâxtâr-e nâzok

Fr.: structure fine   

Closely spaced components seen at high resolution in a → spectral line. The phenomenon is explained by the fact that instead of a single → energy level corresponding to a given value of the → quantum number  n, there are actually a number of energy levels lying close to one another. → fine-structure constant, → fine-structure line.

fine; → structure.

fine-structure constant
  پایای ِ ساختار ِ نازک   
pâyâ-ye sâxtâr-e nâzok

Fr.: constante de la structure fine   

A measure of the strength of → interaction between a → charged particle and the → electromagnetic field. It is a → dimensionless number expressed (in → cgs units) by α = e2c, where e is the → electron charge, ħ is the → reduced Planck's constant, and c is the → speed of light. It is approximately equal to 1/137 or 7.3 x 10-3. The smallness of this number is of great importance since it determines the size of → atoms and the → stability of → matter.

fine structure; → constant.

fine-structure line
  خط با ساختار ِ نازک   
xatt bâ sâxtâr-e nâzok

Fr.: raie de structure fine   

A → spectral line whose → energy levels have a → fine structure. Examples are [C II] 157.7 μm (→ singly ionized carbon), [O III] 88 μm, and [Ne II] 12.8 μm.

fine; → structure; → line.

finger
  انگشت   
angošt (#)

Fr.: doigt   

Any of the terminal members of the hand, especially one other than the thumb (Dictionary.com).

M.E., from O.E. fingor, cognate with Ger. Finger, Du. vinger, O.N. fingr, Goth. figgrs.

Angošt, variants angol, angul (also angal "loop"); Mid.Pers. angust; Av. angušta- "toe," ank- "curved, crooked;" cf. Skt. angustha- "thumb," angula- "finger," ankah "hook, bent;" Gk. angkon "elbow," angkura "anchor;" L. angulum "corner;" Lith. anka "loop;" O.E. ancleo "ankle;" O.H.G. ango "hook;" PIE *ang-/*ank- "to bend".

fingering convection
  همبز ِ انگشتوار   
hambaz-e angoštvâr

Fr.:   

A weak yet important kind of mixing that results from → fingering instability in stars within → radiative zones that have an unstable mean → molecular weight  → gradient. Also called → thermohaline convection.

finger; → -ing; → convection.

fingering instability
  ناپایداری ِ انگشتوار   
nâpâydâri-ye angoštvâr

Fr.: instabilité à traines   

A type of instability that often occurs in fluids which are thermally stably stratified, but have an inhomogeneous composition. A well-known example, found in upper layers of the Earth's oceans, is → salt fingers. Similar fingering instabilities can occur in any other thermally stably stratified solution, provided the concentration of the slower-diffusing solute increases with height. The saturated state of this instability, → fingering convection, takes the form of tightly-packed, vertically-elongated plumes of sinking dense fluid and rising light fluid, and significantly enhances the vertical transport of both heat and chemical composition. The fingering instability occurs in stars within radiation zones that have an unstable mean → molecular weight  → gradient (μ gradient). This situation is often found as a result of material accretion onto a star by anything from a single or multiple planets, to material from a dust-enriched or debris accretion disk, or material from a more evolved companion. It also naturally arises in the vicinity of the → hydrogen shell burning in → red giant branch (RGB) stars, and in thin element-rich layers near the surface of intermediate-mass stars. The fingering instability initially takes the form of thin tubes, hence the name "finger," within which the fluid moves vertically. The tubes rapidly break down, however, as a result of parasitic shear instabilities that develop inbetween them, and the fingering instability eventually saturates into a state of homogeneous fingering convection where the typical aspect ratio of the eddies is closer to one (P. Garaud et al., 2015, arXiv:1505.07759).

finger; → -ing; → instability.

fingers of God
  انگشتان ِ خدا   
angoštân-e Xodâ

Fr.: doigts de Dieu   

A → redshift space distortion which causes the dense central regions of → galaxy clusters to appear elongated along the → line of sight. This effect is attributed to random velocities in clusters of galaxies deviating from pure → Hubble flow. For an observer galaxies with peculiar velocity perpendicular to the line of sight do not change the redshift, which is given just by the normal Hubble expansion. On the contrary, galaxies with peculiar velocity along the line of sight appear with a different redshift, resulting from the Hubble expansion velocity plus the peculiar velocity. Since this affects only redshift and not position on the sky, the stretching occurs only radially, toward the observer. See also → Kaiser effect, → peculiar velocity.

finger; → God.

finite
  کرانمند   
karânmand (#)

Fr.: fini   

1) Math: The opposite of → infinite.
2) Physics: Either non-infinite or non-zero.

From L. finitus, p.p. of finire "to limit, set bounds, end."

Karânmand, from karân "boundary, side, end, coast" + -mand adjective suffix. Karân, variants karâné, kenâr, from Mid.Pers. karân, karânak, kenâr "edge, limit, boundary," Av. karana- "side, boundary, end."

finite population
  پرینش ِ کرانمند   
porineš-e karânmand

Fr.: population finie   

A → statistical population consisting of individuals or items which are finite in number.

finite; → population.

finite series
  سری ِ کرانمند   
seri-ye karânmand (#)

Fr.: série finie   

A sum a1 + a2 + a3 + · · · + aN, where the ai's are real numbers. In terms of Σ-notation, it is written as a1 + a2 + a3 + · · · + aN = Σ (n = 1 to N).  See also → infinite series.

finite; → series.

finite set
  هنگرد ِ کرانمند   
hangard-e karânmand

Fr.: ensemble fini   

A → set whose elements can be numbered from 1 to n, for some positive integer n.

finite; → set.

fire
  آتش، تش، آذر   
âtaš(#), taš (#), âzar (#)

Fr.: feu   

A state, process, or instance of combustion in which a substance combines with oxygen producing heat, light, and flame.

O..E. fyr, from P.Gmc. *fuir (cf. O.N. fürr, M.Du. vuur, Ger. Feuer), from PIE *paewr-; cf. Mod.Pers. Lori porpor "blazing charcoal," Gilaki bur, biur "smokeless red fire" (Lori perisk, periska "spark," Kurd. biriske "spark," Lârestâni pelita "spark"); Tokharian por, puwar "fire;" Gk. pyr "fire;" Hitt. pahhur "fire;" Skt. pū- "to cleanse."

Âtaš, variants âzar, taš, from Mid.Pers. âtaxš, âtur "fire;" Av. ātar-, āθr- "fire," singular nominative ātarš-; O.Pers. ātar- "fire;" Av. āθaurvan- "fire priest;" Skt. átharvan- "fire priest;" cf. L. ater "black" ("blackened by fire"); Arm. airem "burns;" Serb. vatra "fire;" PIE base *āter- "fire."

fireball
  تشگوی، آذرگوی   
tašguy (#), âzarguy (#)

Fr.: boule de feu   

A → meteor that is brighter than the brightest planets, i.e. with an apparent magnitude of -5 or greater. Fireballs are often followed by → meteorite falls. Also called → bolide.

From → fire + ball, from O.E., from O.N. bollr "ball," from P.Gmc. *balluz (cf. O.H.G. ballo, Ger. Ball), from PIE base *bhel- "to swell."

Tašguy, from taš "fire," variant of âtašfire + guy "ball, sphere," variants golulé, gullé, goruk, gulu, gudé (cf. Skt. guda- "ball, mouthful, lump, tumour," Pali gula- "ball," Gk. gloutos "rump," L. glomus "ball," globus "globe," Ger. Kugel, E. clot; PIE *gel- "to make into a ball").

first
  نخست، نخستین، یکم، آغاز   
naxost (#), naxostin (#), yekom (#), âqâz (#)

Fr.: premier   

Being before all others with respect to time, order, importance, etc., used as the ordinal number of one.

O.E. fyrst "foremost," superlative of fore, from P.Gmc. *furisto (cf. O.H.G. furist, O.N. fyrstr, Dan. første, M.Du. vorste "first," Ger. Fürst "prince"), superlative of *fur-/*for-, from PIE *pro- (cf. Av. pouruua- "first," fra- "forward, forth;" Skt. pūrva- "first," pra- "before, formerly," Gk. pro; L. pro; E. fore).

Naxost, from Mid.Pers. naxust "the first," Parthian Mid.Pers. nxwšt, from naxu, Manichean Parthian nwx "beginning" + -ist superlative suffix, Av. -išta-, cf. Skt. -istha-, Gk. -istos, O.H.G. -isto, -osto, O.E. -st, -est, -ost; naxostin, from naxost + suffix -in.
Yekom, from yek, → one, + -om suffix of ordinal numbers.
Âqâz "beginning," from Proto-Iranian *āgāza-, from prefix ā- + *gāz- "to take, receive," cf. Sogdian āγāz "beginning, start," pcγz "reception, taking."

first approximation
  نزدین ِ نخست   
nazdin-e naxost

Fr.: première approximation   

1) Generally, an expression to indicate that a comment or result is only approximate.
2) Math.: In calculus, limiting a differential equation to its → first derivative, for example: ex≅ 1 + x. Also called → linear approximation.

first; → approximation.

first collapse
  رمبش ِ نخست   
rombeš-e naxost

Fr.: premier effondrement   

An early phase in the process of star formation which begins when the mass of a → molecular cloud → clump exceeds the → Jeans mass. The collapse is initially → optically thin to the thermal emission from → dust grains, and the compressional heating rate is much smaller than the cooling rate by the → thermal radiation. The collapse proceeds → isothermally. The isothermal condition is broken when the central density reaches about 10-13 g cm-3 and a small region at the center of the cloud starts to become → opaque. The heat generated by the collapse in this region is no longer freely radiated away, and the compression becomes approximately → adiabatic. The central temperature and pressure then begin to rise rapidly, soon becoming sufficient to decelerate and stop the collapse at the center. There then arises a small central core, called the → first core, in which the material has stopped collapsing and is approaching → hydrostatic equilibrium. Outside this core, the material is still nearly isothermal and continues to fall inward almost in → free fall. Consequently a shock front arises at the boundary of the core, where the infalling material is suddenly stopped. The initial mass and radius of the core are about 1031 g and 6 x 1013 cm, respectively, and the central density and temperature are about 2 x 10-10 g cm-3 and 170 K, respectively. As the collapse proceeds, the core grows in mass due to the infall of the surrounding material; at the same time, however, the core radius decreases because of radiative energy losses from the outer layers of the core. The process leads to the → second collapse (R. B. Larson, 1969, MNRAS 145, 271).

first; → collapse.

first contact
  پرماس ِ نخست   
parmâs-e naxost

Fr.: premier contact   

1) The beginning of a → solar eclipse when the eastern part of the lunar limb touches the western limb of the Sun, marking the beginning of an eclipse.
2) For a → lunar eclipse, the moment when the eastern limb of the Moon is the first to enter the Earth's shadow.

first; → contact.

first core
  مغزه‌ی ِ نخست   
maqze-ye naxost

Fr.: premier cœur   

A first object in → hydrostatic equilibrium predicted to form during early dynamical contraction of a → molecular cloud → clump in the course of the → first collapse.

first; → core.

first degree equation
  هموگش ِ درجه‌ی ِ یکم   
hamugeš-e daraje-ye yekom

Fr.: équiation du premier degré   

A equation in which the highest → exponent of the → variable is 1. Same as → linear equation.

first; → degree; → equation.

<< < -es -iv -ti 21- a p abe abs abs acc acc acc act act ada adi ads aes Age Alb Alf ali all alp alt ama amp ana ang ang ann ano ant ant ape apo app app arc Arg ari art ass ast ast ast atm ato att Aur aut axi azi bac Bal Bar Bar Bay Bec Ber bet bic bij bin bio Bir bla Bla blu blu bol Boo bou bra Bre bro bug C r cal Cal can car Car Cas cat cau cel cen cer Cha cha Cha che chl cir cir cir Cla cli clo clu co- coc coh col col col com com com com com com com com Com con con con con con con con con con con con con Cop Cor cor cor cos cos Cou cou cow cre cri cro cry cur cut Cyg dam dar dat de deb dec dec ded def deg del dem den dep des det dev dia dif dif dig dio Dir dis dis dis dis dis dis div don dou dow dro dur dwa dyn Dys ear ebb ecl edg egg Ein Ela ele ele ele ele ell eme emp enc eng ent epi equ equ Equ esc eth Eur eve exa exc exe exi exp exp ext ext eye fac fal Far fed fer fer fie fin fir fit fla flo flu fol for for Fou fra fre Fre fro fuz gai Gal Gal gam gas Gau gen gen geo geo geo gia glo gol gra gra gra gra gre gri gui H I hai Ham har Hau hea hec hel hel her HES hie hig his hom hor hot Hub hum Huy hyd hyd hyl hyp ice ide ima imp imp imp inc ind ind ine inf inf inf ini ins ins ins int int int int Int int int int inv ion iro irr iso iso ite jel Jou Jup kao Kep kil Kip Kra Lag Lam lan lar las law lea leg Leo lex lig lim lin lin lin lit Loc loc log Lor low lum lun lun Lym mac mag mag mag mag mag mai Mal mar mas mas mat max mea mec meg men mer met met met mic mic Mik min min mis mob mod mol mon moo mou mul mul mys nan Nat nau nec neo neu nev New NGC no nom non non nor not nuc nuc num nut obj obs obs occ odd OH Ome Oor ope opp opt opt orb ord ori ort osc out ove oxi pai Pan par par par par pas pea pen per per per per Per per pha phl pho pho pho pi pip Pla pla pla pla ple poa pol Pol pol pol pop pos pos pot pra pre pre pre pri pri pri pro pro pro pro pro pro pro Pto pul puz qua qua qua qua qui rad rad rad rad rad rad rai ran rar Ray rea Rea rec rec red red ref ref reg rel rel rel rep res res res res ret Rhe rid rig ris Roe Ros rot rub rut Sag sam sat sca sca Sch sci sea sec sec see sel sem sen ser Sh2 sha shi sho sid sig sim sin Sir ske sli Smo soc sol sol sol sol sol sou spa spa spe spe spe spe sph spi spo Squ sta sta sta sta ste ste ste sto str str str sub sub sub sum sup sup sup sup sur sus sym syn T d tap tec tem ten tes the the the the thi thr tid tim tip ton tor tow tra tra tra tra tri tri tru tub tur two Typ ult un- und uni uni unp upp urg V20 Van var veg vel ver vib vio vir vis Vol Vul wan wat wav WC4 wea wel whi Wil wis WNL wor X-r Yer Z s zer [C > >>