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 p abe abs abs aca acc acc acr act ada adh Adr aer AGB air Alf Alg all alp alt AM amo ana And ang ani ano Ant Ant apa apo app app Ara Arc ari Arr ash ass ast ast asy atm ato att aut ave axi Bab bal Bal bar bar bea Bek Bes bia Big bin bin bip biv bla bli blu Boh Bol Bos bou bra bri bro buo cal cal can cap car Car cat cat CCD Cen cen CH cha cha che Che chr cir cir cit 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 con Cop Cor cor cor cos cos cou cou Cow cre cri cro cry cur cya Cyg dan dar dat de- deb dec dec ded def deg del dem den dep des det dev dia dif dif dih dio Dir dis dis dis dis dis dis DO 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 ext fac fal far fed Fer fer fie fin fir fis fla flo flu fol for for fou fra fre Fre fro fut G-t gal gal gam gas Gau Gem gen geo geo geo gia Gli Gol gra gra gra gra gre gri gui H I Hag hal har hat He- hea hel Hel her Hes hie hig his hom hor hot Hub Hug hur hyd hyd hyg hyp ice ide ima Ima imp imp inc inc ind ine inf inf inf ing inn ins ins int int int int int int int int inv Io ion iro isl iso iso Jac jet jud jur Kel Kep kil Klo Kui Lag lam Lap Lar lat law lea len lep Lib lig lim lin lin Lio lit loc LOF lon Lor low lum lun Lup Lyo mac mag mag mag mag mag mai man Mar mas mas mat Max mea mec Meg Mer Mer met met Met mic Mid Mil min Mir mit mod mod mol mon Mor 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 ocu oft 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 phi pho pho pho phy pio Pla pla pla pla Pla plu Poi pol pol pol poo pos pos pot pra pre pre pre pre pri pri pro pro pro pro pro Pro pro pse pul pur qua qua qua qua que rac rad rad rad rad rad rad ran rar ray rea rea rec rec red red ref ref reg rel rel rel ren res res res res ret rev Ric rig rin roc roo rot rot Rus Sac sal sat sca sca Sch sci Scu sec sec Sed sel Sel sen ser Sex Sha she sho sid sig sil sim sin siz sla Sma sno sof sol sol sol sol sou sou spa spa spe spe spe sph spi spi spr squ sta sta sta sta ste ste ste Sto Str str str sub sub suc sun sup sup sup sup sur swa syn syn tab tar tek tem ter tes the the the the Tho thr tid tim Tis Too Tor tra tra Tra tra tra tri tri tru Tul tur two Typ ult un- und uni uni unk upp Urc utt val var vec vel ver vib vio vir vis voi vor wan wat wav wax wea Wei whi Wil win WN9 wor X-r yel you zer zod > >>

Number of Results: 13048 Search : far
dative case
  کاته‌ی ِ برایی   
kâte-ye barâyi

Fr.: cas datif   

The form of a word (in Latin and other inflected languages) indicating the noun or pronoun for which an action happens or a quality exists. In English loosely used for → indirect object (for example, him in Give him the book).

From L. casus dativus ("case for giving"), a translation of Gk. dotike ptosis ("inflection for giving"), from dativus "pertaining to giving," from datus "given" (from PIE root *do- "to give"), → datum; → case.

Kâte, → case; barâyi, adj. of barâye, "→ because of," "→ for."

datum
  ۱) داده؛ ۲) داده‌بن؛ ۳) فرازبن   
1) dâdé (#); 2) dâdebon; 3) farâzbon

Fr.: donnée   

1) A single piece of information, as a fact, statistic, or code.
2) Any numerical or geometric quantity which serves as a reference or a base for measurement of other quantities.
3) Surveying: Any basis level (surface, line, or point) used as a reference in measuring elevations.

L. datum "given," neuter p.p. of dare "to give, offer," cf. Av. and O.Pers. dā- "to give, grant, yield," Av. dadāiti "he gives," Skt. dadáti "he gives," Gk. didomi "I give," PIE base *do- "to give."

Dâdé "given," p.p. of dâdan "to give," Mid.Pers. dâdan "to give," O.Pers./Av. dā- "to give, grant, yield," akin to L. data, as above.
Dâdebon, from dâdé "datum," + bon "basis, base," → element.
Farâzbon, from farâz "above, up, upon," → height, + bon "basis, base," as above.

daughter
  دختر   
doxtar (#)

Fr.: noyau fils   

A term used in → nuclear physics to denote a → nuclide produced by the → radioactive decay of a → parent nuclide.

From M.E. doughter, O.E. dohtor, from P.Gmc. *dochter (Ger. Tochter), from PIE *dhug(h)əter-; cf. Av. dugədar-, duγdar-, Mod.Pers. doxtar, Skt. duhitár-, Gk. thygater, Arm. dowstr, Lith. dukte.

Doxtar, from Mid.Pers. duxtar, duxt, O.Pers. *duxçi-, Av. dugədar-, duγdar-, cognate with daughter, as above.

daughter product
  دختر   
doxtar (#)

Fr.: noyau fils   

In → nuclear physics, same as → daughter.

daughter; → product.

Davisson-Germer experiment
  آزمایش ِ دیویسون-جرمر   
âzmâyeš-e Davisson-Germer

Fr.: expérience de Davisson-Germer   

The experiment carried out in 1927 that confirmed the → de Broglie hypothesis as to the → wave nature of the → electron. It showed that electrons scattering off crystals form a → diffraction pattern. The experimental setup consisted of a → nickle chloride → crystal as → target, an electron gun, and a → detector placed on a graduated circular scale. The intensity of the reflected electrons was measured as a function of angle and electron energy. The observations showed a strong intensity peak at a certain angle. The nickel crystal acted as a → diffraction grating. → Constructive interference occurred at a particular angle, where the peak intensity was observed in accord with → Bragg's law. Interestingly, the intent of the initial experiment was was not to confirm the de Broglie hypothesis. In fact, the discovery was made by accident.

Carried out by American physicists Clinton Davisson (1881-1958) and Lester Germer (1896-1971); → experiment.

dawn
  پگاه، سپیده دم، بامداد   
pegâh (#), sepidedam (#), bâmdâd (#)

Fr.: aube, point du jour, aurore   

The first daylight in the sky before sunrise, equivalent to morning astronomical → twilight; opposed to → dusk.

M.E. dawen (v.), from O.E. dagung, from dagian "to become day," from root of dægday.

Pegâh, from Mid.Pers. pa gâh, literally "soon; near the time (of sunrise)," from pa "to; for; in; on; with; by; according to," O.Pers. upā, Av. upa "toward, with, on, in, in the time of" (cf. Skt. úpa "toward, together with, under, near to, on," Gk. hypo "under, below," L. sub "under," Ger. auf, E. up; PIE *upo "under, up from under, over") + gâh "time," O.Pers. gāθu-, Av. gātav-, gātu- "place, throne, spot" (Skt. gátu- "going, motion; free space for moving; place of abode," PIE *gwem- "to go, come").
Sepidedam, from sepidé "whitish; dawn," from sepid "white" (Mid.Pers. spêt, Av. spita- "white," Skt. śveta- "white," Lith. sviesti "to shine," svaityti "to brighten," P.Gmc. *khwitaz, O.E. hwit, E. white, Ger. weiss, PIE *kwintos/*kwindos "bright") + dam "moment, time; to blow, breathe; smoke" (Mod./Mid.Pers. damidan "to blow, breathe," Av. dāδmainya- "blowing up," Skt. dahm- "to blow," dhámati "blows," Gk. themeros "austere, dark-looking," Lith. dumti "to blow," PIE dhem-/dhemə- "to smoke, to blow").
Bâmdâd, from Mid.Pers. bâmdât, Av. bāmya- "the dawn," from bā- "to shine" (cf. Skt. bhā- "light, brightness," Gk. phainomai "to appear, shine, gleam," Arm. banam "to open, uncover," PIE *bhā- "to shine").

Dawn spacecraft
  فضاناو ِ داؤن   
fazânâv-e Dawn

Fr.: sonde spatiale Dawn   

NASA's mission to explore the two largest objects in the → asteroid belt, the asteroid Vesta and the → dawarf planet Ceres, gathering data relating to their composition, internal structure, density and shape. Launched in September 2007, Dawn entered the orbit of → Vesta in July 2011 and spent 16 months there before leaving for → Ceres. It entered Ceres orbit on March 6, 2015. The Dawn spacecraft is made of aluminium and graphite composite, it has a dry mass of 747.1 kg and a mass of 1217.7 kg when fully fuelled prior to launch. The spacecraft is a box-shaped design measuring 1.64m × 1.27m × 1.77m. Dawn ran out of fuel on Nov. 1, 2018, but the spacecraft will continue to orbit Ceres for several decades.

dawn; → spacecraft.

day
  روز   
ruz (#)

Fr.: jour   

The length of time it takes Earth (or a planet) to rotate once on its axis relative to some external reference. The day is measured in several ways, depending on this reference, → sidereal day; → solar day; → mean solar day.

M.E., from O.E. dæg (cf. Ger. Tag, Swedish and Danish dag "day"), from PIE base *dhegh- "to burn." Not related to L. dies "day" (from *dyeu- "to shine," → diurnal), but rather to Av. dag- "to burn," dažaiti "burns," Mod.Pers. dâq "hot," Skt. dah- "to burn," dáhati, Gk. tephra "ash," L. fovere "to boil," Albanian djeg "to burn," Russ. žeč' "to burn," Lith. dagas "hot season," degti "to burn," O.Prus. dagis "summer."

Ruz "day," from Mid.Pers. rôc, O.Pers. raucah-, Av. raocah- "light, luminous; daylight," Skt. roka- "brightness, light," cognate with Gk. leukos "white, clear," L. lux "light" (also lumen, luna), PIE base *leuk- "light, brightness". The Persian words rowšan "bright, clear," foruq "light," and afruxtan "to light, kindle" also belong to this family, as well as the E. light, Ger. Licht, and Fr. lumière.

daylight meteor
  شهاب ِ روز   
šahâb-e ruz

Fr.: météore de jour   

A → meteor detected using → radar techniques during daylight or when skies are cloudy.

day; → light; → meteor.

daylight saving time
  وخت ِ نور‌اندوزی، وقت ِ ~   
vaxt-e nur anduzi, vaqt-e ~

Fr.: heure d'été   

A system of adjusting the official local time in some countries in order to provide a better match between the hours of daylight and the active hours of work and school. The "saved" daylight is spent on evening activities which get more daylight, rather than being "wasted" while people sleep past dawn. Although known also as summer time, it includes the spring season and nearly half of autumn.

day; → light; saving, from save, from O.Fr. sauver, from L.L. salvare "to secure," from L. salvus "safe," PIE *solwos, from base *sol- "whole" (cf. O.Pers. haruva-, Av. haurva- "whole, intact," Mod.Pers. har "every, all; any," Skt. sarva- "whole, entire," Gk. holos "whole"); → time.

Vaxt, written vaqtوقت but pronounced vaxtوخت, is a Pers. word meaning "portion (of time)". Its variants and related words in Mod./Mid.Pers. are: baxt "what is alloted, fate, fortune," baxš "portion, part, division," baxšidan, baxtan "to divide, distribute, grant," Av. base bag- "to attribute, allot, distribute," baxš- "to apportion, divide, give to," baxta- "what is alloted (luck, fortune)," baxədra- "part, portion," baγa- "master, god," O.Pers. bāji- "tribute, tax," cf. Skt. bhaj- "to share, divide, distribute, apportion," bhájati "divides," bhakta- "alloted; occupied with; a share; food or a meal, time of eating?," Gk. phagein "to eat (to have a share of food)"; PIE base *bhag- "to share out, apportion."
nurlight.
anduzi, verbal noun of anduxtan "to save; acquire, gather," from Mid.Pers. handôxtan, handôz- "to gain, acquire, amass," from *ham-tuj-, from ham- "together," → com- + *tuj- "to save, gather, (re)pay," cf. Skt. tuj- "to promote, be strong, move quickly."

daytime
  روز‌هنگام   
ruzhangâm (#)

Fr.: temps de jour   

The time interval when the Sun is above the horizon for a given position.

day; → time.

Ruzhangâm, from ruzday + hangâm "time, hour, season," Mid.Pers. hangâm "time, epoch, season," Av. ham-gam- "to meet together," from ham- "together," → com- + gam- "to come; to go," jamaiti "goes," O.Pers. gam- "to come; to go," Mod.Pers. âmadan "to come," Skt. gamati "goes," Gk. bainein "to go, walk, step," L. venire "to come," Tocharian A käm- "to come," O.H.G. queman "to come," E. come; PIE root *gwem- "to go, come."

DB white dwarf
  سفید‌کوتوله‌ی ِ DB   
sefid kutule-ye DB

Fr.: naine blanche DB   

A → white dwarf whose spectrum shows strong He I in the absence of hydrogen or metal lines.

D short for → dwarf; B a convention; → white.

DC white dwarf
  سفید‌کوتوله‌ی ِ DC   
sefid kutule-ye DC

Fr.: naine blanche DC   

A → white dwarf showing a continuous spectrum with no readily apparent lines.

D short for → dwarf; C a convention; → white.

de Broglie equation
  هموگش ِ دوبروی   
hamugeš-e de Broglie

Fr.: équation de de Broglie   

According to the → de Broglie hypothesis, which has been verified by experiments, every → particle of matter, whatever its nature, has a characteristic → wavelength associated with its wavelike quantum aspect. The de Broglie equation gives the equivalent wavelength of a moving particle: λ = h/mv, where h is → Planck's constant, m the mass of the particle, and v its velocity.
See also: → de Broglie wavelength, → Davisson-Germer experiment.

Named after Louis Victor de Broglie (1892-1987), French physicist, creator of a new field in physics, wave mechanics, who won the Nobel prize in physics in 1929. → equation

de Broglie hypothesis
  انگاره‌ی ِ دوبروی   
engâre-ye de Broglie

Fr.: hypothèse de de Broglie   

The suggestion by Louis de Broglie in 1924 whereby if → electromagnetic waves possess particle properties (→ particle nature), then it might be reasonable to suppose that material particles, such as → electrons, should possess wave properties (→ wave nature). The de Broglie hypothesis was based on the intuitive feeling that nature seems to have strong attachment to symmetry. In other words, if radiation has particle-like properties, then material particles should possess wave-like properties. At the time no direct experimental evidence was present for the validity of this suggestion. The first confirmation of de Broglie's hypothesis was provided by the → Davisson-Germer experiment. See also → wave-particle duality;

de Broglie equation; → hypothesis.

de Broglie wavelength
  موج-طول ِ دوبروی   
mowjtul-e de Broglie

Fr.: longueur d'onde de Broglie   

The wavelength of the wave associated with a → particle as given by the → de Broglie equation.

de Broglie equation; → wavelength.

de Sitter Universe
  گیتی ِ دوسیتر   
giti-ye de Sitter

Fr.: Univers de de Sitter   

A solution to → Einstein's field equations of → general relativity which contains no ordinary matter (ΩM = 0) or radiation (ΩR = 0), is → Euclidean (k = 0), but has a → cosmological constantΛ > 0). The Universe expands exponentially forever. This solution was the first model expanding of → expanding Universe. See also → empty Universe, → Milne Universe.

After the Dutch mathematician and physicist Willem de Sitter (1872-1934) who worked out the model in 1917; → universe.

de Vaucouleurs law
  قانون ِ دووکولور   
qânun-e de Vaucouleurs

Fr.: loi de Vaucouleurs   

A mathematical expression describing the → surface brightness profile of a typical → elliptical galaxy, whereby the projected luminosity distribution varies as exp(-R)1/4.

de Vaucouleurs radius; → law.

de Vaucouleurs radius
  شعاع ِ دووکولور   
šo'â'-e de Vaucouleurs

Fr.: rayon de Vaucouleurs   

An → isophotal radius of a galaxy, where the → surface brightness in the B band falls to 25 mag arcsec-2.

After the French-born American astronomer Gérard de Vaucouleurs (1918-1995); → radius.

de Vaucouleurs system
  راژمان ِ دووکولور   
râžmân-e de Vaucouleurs

Fr.: système de Vaucouleurs   

A widely used scheme for classifying galaxies which is an extension to the → Hubble sequence Hubble sequence. De Vaucouleurs introduced a more elaborate classification system for spiral galaxies (→ spiral galaxy) based on three morphological characteristics:
1) Bars. Galaxies are divided on the basis of the presence or absence of a nuclear → stellar bar. SA denotes spiral galaxies without bars, complementing Hubble's use of SB for → barred spirals. De Vaucouleurs also defined an intermediate class, SAB, containing weakly barred spirals. → Lenticular galaxies are also classified as unbarred (SA0) or barred (SB0), with the notation S0 reserved for those galaxies for which it is impossible to tell if a bar is present or not.
2) Rings. Galaxies possessing ring-like structures are denoted (r), those without rings (s), and transition galaxies (rs).
3) Spiral arms. These are divided into the following subclasses: Sd (SBd), that is diffuse, broken arms made up of individual stellar clusters and nebulae; very faint central → bulge; Sm (SBm): irregular in appearance; no bulge component; and Im, that is highly irregular galaxy.
Galaxies in the classes Sm and Im are termed the → Magellanic spirals and irregulars, respectively. The → Large Magellanic Cloud is of type SBm, while the → Small Magellanic Cloud is an irregular (Im).

de Vaucouleurs radius; → system.

<< < -es -iv -ti 21 a p abe abs abs aca acc acc acr act ada adh Adr aer AGB air Alf Alg all alp alt AM amo ana And ang ani ano Ant Ant apa apo app app Ara Arc ari Arr ash ass ast ast asy atm ato att aut ave axi Bab bal Bal bar bar bea Bek Bes bia Big bin bin bip biv bla bli blu Boh Bol Bos bou bra bri bro buo cal cal can cap car Car cat cat CCD Cen cen CH cha cha che Che chr cir cir cit 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 con Cop Cor cor cor cos cos cou cou Cow cre cri cro cry cur cya Cyg dan dar dat de- deb dec dec ded def deg del dem den dep des det dev dia dif dif dih dio Dir dis dis dis dis dis dis DO 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 ext fac fal far fed Fer fer fie fin fir fis fla flo flu fol for for fou fra fre Fre fro fut G-t gal gal gam gas Gau Gem gen geo geo geo gia Gli Gol gra gra gra gra gre gri gui H I Hag hal har hat He- hea hel Hel her Hes hie hig his hom hor hot Hub Hug hur hyd hyd hyg hyp ice ide ima Ima imp imp inc inc ind ine inf inf inf ing inn ins ins int int int int int int int int inv Io ion iro isl iso iso Jac jet jud jur Kel Kep kil Klo Kui Lag lam Lap Lar lat law lea len lep Lib lig lim lin lin Lio lit loc LOF lon Lor low lum lun Lup Lyo mac mag mag mag mag mag mai man Mar mas mas mat Max mea mec Meg Mer Mer met met Met mic Mid Mil min Mir mit mod mod mol mon Mor 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 ocu oft 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 phi pho pho pho phy pio Pla pla pla pla Pla plu Poi pol pol pol poo pos pos pot pra pre pre pre pre pri pri pro pro pro pro pro Pro pro pse pul pur qua qua qua qua que rac rad rad rad rad rad rad ran rar ray rea rea rec rec red red ref ref reg rel rel rel ren res res res res ret rev Ric rig rin roc roo rot rot Rus Sac sal sat sca sca Sch sci Scu sec sec Sed sel Sel sen ser Sex Sha she sho sid sig sil sim sin siz sla Sma sno sof sol sol sol sol sou sou spa spa spe spe spe sph spi spi spr squ sta sta sta sta ste ste ste Sto Str str str sub sub suc sun sup sup sup sup sur swa syn syn tab tar tek tem ter tes the the the the Tho thr tid tim Tis Too Tor tra tra Tra tra tra tri tri tru Tul tur two Typ ult un- und uni uni unk upp Urc utt val var vec vel ver vib vio vir vis voi vor wan wat wav wax wea Wei whi Wil win WN9 wor X-r yel you zer zod > >>