An Etymological Dictionary of Astronomy and Astrophysics
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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 aga air Alf Alg alk Alp alt alu amm ana And ang ani ano ant ant Ap apo app app Aqu Arc arg arr asc ass ast ast asy atm ato att aur aut axi B-m bad Bal bar bar Bay Bed ber Bet bif bim bin bio bis bla ble blu Bod Bol bor bou Bra Bre bro bul C-t Cal Cam can car Car Cas cat cav 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 coo Cor Cor cor cos cos cos Cou cou Cra Cre cri cro cub cur cyc cyl Dan dat Dav de- Deb dec dec dee def deg del Den den der det deu dew dic dif dif dil Dip dir dis dis dis dis dis diu dod Dop dou Dra dua dus dwa dyn DZ Ear ecc eco edi EHB Ein ela ele ele ele ele ell eme emp end Eng ent epi equ equ era ESP eth Eur evi exa exc exe exi exp exp ext ext ext fac fal far fec Fer fer fie fin fir fis fla Flo flu fog for for Fou fra fre fre Fro fun G s Gal gal gal Gar gau geg gen geo geo geo ger gla gly gra gra gra gra gra Gre gro GYR Had Hal hap Har HD hea hel hel Hen Her hex hig Hil hol Hoo hor hou Hub hum hyb hyd hyd hyp hys ide ign ima imp imp in- inc Ind ind ine inf inf inf ini ins ins ins int int int int Int int int int inv ion iri irr iso iso iso Jea Jor jum K c Kep Ker kin kno lab Lam Lan Lap las lat Le lef len lev lig lig lin lin lin liq Lit loc log lon lou LS lun lun Lym M s Mag mag mag mag mag mag maj man Mar mas mas mat May mea mec mel mer mes met met met mic mid mil Min Mir mix mod mod mol mon mor mov mul mur mys nan nat nav nec Nep neu New New NGC nob nom non non nor nos nuc nuc num nut obj obl obs occ oct off oli oni ope opp opt opt orb ord org orp osc out ove oxi P-w pal par par par par Pas pat pej per per per per per per pha Phe pho pho pho phy pin pla Pla pla pla pla plu poi pol pol Pol pol por pos pot Poy pre pre pre pre pri pri pri pro pro pro pro pro pro Psa pul pum Q i qua qua qua qua R A rad rad rad rad rad rad Ram Ran rat rea rea rec rec red red ref ref reg rei rel rel rem rep res res res ret rev Rho Rie ril riv rog Ros rot rul S A Sag sam sat sca sca Sch Sco Sec sec sec seg sel sem sen set Sha sha shi sho sid sig sim sin Sir ske sli Smo soc sof sol sol sol sol sou sou spa spe spe Spe spe sph spi Spi spr sta sta sta sta sta ste ste ste Sto str str sub sub sub suc sun sup sup sup sup sur swa syn syn tac tas tel tem ter tes the the the the thi thr tid til tip ton tor tou tra tra tra tra Tri tri tru tsu tur two Typ UHE ult unc uni uni uni upg ura uti val var vec Vel ver Ver vie Vir vis vis vol W-R war wav wav wea Wei wha wid win WN3 Wol wri xen yok zen zij > >>

Number of Results: 13116 Search : far
utility software
  نرم‌افزار ِ هوده‌مند   
narm-afzâr-e hudemand

Fr.: logiciel utilitaire   

A part of the system software designed to support the operation of application software and is used to manage the computer files. Examples of utility software are disk diagnosis program, backup software, password generation software, and virus protection software. Also called utilities.

utility; → software.

utilization
  هودش   
hudeš

Fr.: utilisation   

The act or process of utilizing.

Verbal noun of → utilize.

utilize
  هودیدن   
hudidan

Fr.: utiliser   

To make practical or worthwhile use of.

From Fr. utiliser, from It. utilizzare, from utile "usable," from L. utilis "usable," from uti "to use."

Hudidan, from hudé, hudag "use," → utility, + -idan.

Utopia Planitia
  دشت ِ ناکجا، ~ ناکجا‌آباد   
dašt-e nâkojâ, ~ nâkojâ âbâd

Fr.: Utopia Planitia   

A → plain in the northern hemisphere of Mars that was chosen as the landing site of the Viking II space probe on September 3, 1976.

Mod.L. Utopia, literally "nowhere," coined by Thomas More (1516), from Gk. ou "not" + topos "place;" planitia, from planus, → plain.

Dašt, → plain; nâkojâ "nowhere," from nâ-, → un-, + kojâ "where?; a place;" Mid.Pers. kugiyâg, from "where; that; than" + giyâk "place" (O.Pers. ā-vahana- "place, village;" Av. vah- "to dwell, stay," vanhaiti "he dwells, stays;" Skt. vásati "he dwells;" Gk. aesa (nukta) "to pass (the night);" Ossetic wat "room; bed; place;" Tokharian B wäs- "to stay, wait;" PIE base ues- "to stay, live, spend the night"); nâkojâ âbâd literally "city of nowhere, habitation of nowhere," from nâkojâ, as explained, + âbâd "city; habitation; cultivated" (Mid.Pers. âpât, âpâtân "cultivated, inhabitated;" Proto-Iranian *ā-pāta- "protected," from prefix ā + pā- "to protect, guard" (Mod.Pers. pâyidan), → observe.

utter
  واپیدن   
vâpidan

Fr.: prononcer, proférer, pousser   

1) To give audible expression to; speak or pronounce.
2) Phonetics: To produce (speech sounds, speech-like sounds, syllables, words, etc.) audibly, with or without reference to formal language (Dictionary).

M.E. outren from M.Du. uteren or M.L.G. utern "to turn out, show, speak," from uter "outer," comparative adj. from ut, → out.

Vâpidan, from Proto-Ir. *uab-/*uaf- "to utter (sing, speak), to call;" cf. Av. uf- "to sing;" Sogd. w'β, w'b "to say, speak;" Baluci gwâpt/gwâp- "to summon, call together;" Mod.Pers. gap, gab "word, chit-chat," zand-bâf "nightingale," buf "owl."

utterance
  واپش   
vâpeš

Fr.: parole, déclaration   

1) An act of uttering; a spoken word, statement, or vocal sound.
2) Something uttered; a word or words uttered; a cry, animal's call, or the like.
3) Linguistics: Any speech sequence consisting of one or more words and preceded and followed by silence: it may be coextensive with a sentence (Dictionary.com).

utter; → -ance.

uvby system
  راژمان ِ uvby   
râžmân-e uvby

Fr.: système photométrique uvby   

A four-color stellar → photometric system devised by B. Strömgren. It is based on measurements in the ultraviolet (3500 Å), violet (4100 Å), blue (4670 Å), and yellow (5470 Å) regions of the spectrum. The filters bandwidths are 340, 200, 160, and 240 Å respectively. Also known as Strömgren four-color photometry.

u, v, b, and y referring to ultraviolet, violet, blue, and yellow respectively; → system.

UX Ori star
  ستاره‌ی ِUX شکارگر   
setâre-ye UX Šekârgar

Fr.: étoile UX Ori   

A star that shows large irregular brightness variations and belongs to the Herbig Ae/Be family, i.e. pre-main sequence stars of intermediate mass. Typically a decrease of 2-3 magnitudes in the visible occurs for a few days to a couple of weeks. Current theories explain this behavior as being an obscuration of the central star by orbiting dust clouds, as well as contribution to the total luminosity by unsteady accretion onto the central star. Also called UXOr.

U and X letters of alphabet, Ori, → Orion; → star.

V2052 Ophiuchi
  V2052 مار‌افسا   
V2052 Marafsâ

Fr.: V2052 Oph   

A hot star of → apparent visual magnitude V = 5.82 lying in the constellation → Ophiuchus, also known as HR 6684, HD 163472, and HIP 87812. V2052 Oph is of → subgiant  → spectral type B2 IV-V and belongs to the family of magnetic → Beta Cephei → pulsators. It has a luminosity of 620 Lsol, a radius of 6.83 Rsol and lies about 830 → light-years away. Three stellar pulsation modes have been detected and studied from ground-based spectroscopy and multi-color photometry. Its magnetic field was deduced to be → dipolar dipolar with a strength of ~ 400 G, inclined 35° to the rotation axis. The star's → convective overshooting region is small, with no extra mixing in spite of the relatively large rotational velocity. This clearly illustrated the effect of the magnetic field: the inhibition of chemical mixing processes by the magnetic field. This result is in agreement with theoretical criteria, which predict that a surface magnetic field of ~ 70 G is sufficient to limit the overshooting in this star. V2052 Oph is now considered as a prime example of what magneto-asteroseismology can achieve (Neiner et al., 2012, A&A, 537, A148).

variable star designation.

vacuum
  خلاء   
xala' (#)

Fr.: vide   

1) A space completely empty of matter but not achievable in practice on Earth.
2) A state of lowest energy in a → quantum field theory.

L. vacuum "an empty space, void," noun use of neuter of vacuus "empty," related to vacare "to be empty."

Xala' loan from Ar.

vacuum birefringence
  دوشکست ِ دوخلأیی   
došekast-e jala'i

Fr.: biréfringence du vide   

A highly → magnetized vacuum behaving as a prism for the propagation of light, as predicted by → quantum electrodynamics (QED). Attempts to detect this phenomenon in the laboratory have not yet succeeded in the 80 years since it was predicted (Heisenberg & Euler, 1936, Z. Physik, 98, 714). This effect can be detected only in the presence of enormously strong → magnetic fields, such as those around → neutron stars. Owing to the large inferred magnetic fields (B ~ 1013 G, → gauss), radiation from these sources is expected to be substantially polarized, independently of the mechanism actually responsible for the → thermal emission. The strongest magnetic field so far created in a laboratory is less than 106 G lasting only for several tens of milliseconds. A large observed → polarization degree is, however, expected only if QED polarization effects are present in the magnetized vacuum around the star. The detection of a strongly → linearly polarized signal would therefore provide the observational evidence of QED effects in the strong-field regime. Recently a team of astrophysicists (Mignani et al. 2016, arXiv/1610.08323) have detected → linear polarization toward the neutron star RXJ1856.5-3754 (at a significant degree of around 16%). This finding is likely due to the boosting effect of vacuum birefringence occurring in the area of empty space surrounding the neutron star.

vacuum; → birefringence.

vacuum chamber
  اتاقک ِ خلاء   
otâqak-e xala'

Fr.: chambre à vide   

An enclosure from which air is removed.

vacuum; → chamber.

vacuum energy
  کاروژ ِ خلاء   
kâruž-e xala'

Fr.: énergie du vide   

In particle physics the lowest energy allowed by field quantization when all fields are in their → ground states. Vacuum energy is predicted to arise from → virtual particles that fluctuate in and out of existence, as manifested by the → Casimir effect. The cosmological → dark energy is postulated to be related to vacuum fluctuations. There is however an enormous discrepancy with the predictions of quantum field theory. In this theory the value of vacuum energy density is expected to be roughly of the order ρvEmax4, where Emax is the maximum energy at which the field theory is valid. At energies of the order of the → Planck energy, EPl≅ 1019 GeV, vacuum energy might be roughly: ρvEPl4≅ 1076 GeV4. On the other hand, the vacuum energy density in standard cosmological model is given by: ρΛ = ΩΛcrit, where ΩΛ is the → density parameter for the → cosmological constant and ρcrit is the → critical density. More explicitly, ρΛ = ΩΛ . 3 H2/(8πG). Using present-day values of ΩΛ (0.7) and H (70) leads to ρΛ = 10-46 GeV4. Therefore, the discrepancy between the prediction and the observed value is 122 orders of magnitude.

vacuum; → energy.

vacuum polarization
  قطبش ِ خلاء   
qotbeš-e xala'

Fr.: polarisation du vide   

A quantum field theory a process in which an electromagnetic field gives rise to virtual electron-positron pairs that in turn exert electromagnetic fields of their own, in a manner similar to classical dielectric polarization.

vacuum; → polarization.

vague
  گرنگ   
gereng

Fr.: vague   

1) Not clearly or explicitly stated or expressed.
2) Indefinite or indistinct in nature or character, as ideas or feelings.
3) Not definitely established, determined, confirmed, or known; uncertain (Dictionary.com). → ambiguous, → nebulous, → indefinite, → fuzzy, → unclear.

M.E., from M.Fr. vague "empty, vacant; wild, uncultivated; wandering," from L. vagus "wandering, rambling," of unknown origin.

Gereng, from Kalidari gereng "wandering," Kurd. (Kurmanji) garin, (Sorani) garân "to wander," Dehxodâ gereng "shattered;" ultimately from Proto-Ir. *gar-an-ka-, from *gar- "to turn, to wind" (Cheung 2007).

vague year
  سال ِ گردان، ~ گرنگ   
sâl-e gardân, ~ gereng

Fr.: année vague   

A year of 365 days that overlooks the fraction of less than 0.25 days corresponding to the whole length of the → tropical year. The vague year was used in the → calendars of ancient Egypt, Iran, Mayas, and some other civilizations. Typically the vague year was divided into 12 months of 30 days each plus 5 → epagomenal days.

From annus vagus "wandering year;" → vagueyear.

valence
  ارزایی   
arzâyi

Fr.: valence   

A measure of the number of chemical bonds formed by the atoms of a given element. It represents the relative ability of an atom of an element to combine with other atoms. For example, the valence of O in water, H2O, is 2. Also called valency.

M.E., from O.Fr., from L valentia "strength, worth," from valentem (nominative valens), pr.p. of valere "to be strong."

Arzâyi, noun from arzâ, agent noun/adj. from arzidan "to be worth," arzân "worthy; of small value, cheap," arj "esteem, honour, price, worth" (Mid.Pers. arz "value, worth," arzidan "be worth," arzân "valuable;" Av. arəjaiti "is worth," arəja- "valuable," arəg- "to be worth;" cf. Skt. arh- "to be worth, to earn," árhant- "worthy person;" Gk. alphanein "to bring in as profit," alphein "to ear, obtain;" Lith. algà "salary, pay;" PIE base *algwh- "to earn; price, value").

valence band
  باند ِ ارزایی   
bând-e arzâyi

Fr.: bande de valence   

The range of energy states in the spectrum of a solid crystal which includes the energies of all the electrons binding the crystal together.

valence; → band.

valence electron
  الکترون ِ ارزایی   
elektron-e arzâyi

Fr.: électron de valence   

An electron of an atom lying farthest from the nucleus. Valence electrons are shared when atoms combine to form molecules.

valence; → electron.

valency
  ارزایی   
arzâyi

Fr.: valence   

Same as → valence.

<< < -es -iv -ti 21 a p abe abs abs aca acc acc acr act ada adh Adr aer aga air Alf Alg alk Alp alt alu amm ana And ang ani ano ant ant Ap apo app app Aqu Arc arg arr asc ass ast ast asy atm ato att aur aut axi B-m bad Bal bar bar Bay Bed ber Bet bif bim bin bio bis bla ble blu Bod Bol bor bou Bra Bre bro bul C-t Cal Cam can car Car Cas cat cav 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 coo Cor Cor cor cos cos cos Cou cou Cra Cre cri cro cub cur cyc cyl Dan dat Dav de- Deb dec dec dee def deg del Den den der det deu dew dic dif dif dil Dip dir dis dis dis dis dis diu dod Dop dou Dra dua dus dwa dyn DZ Ear ecc eco edi EHB Ein ela ele ele ele ele ell eme emp end Eng ent epi equ equ era ESP eth Eur evi exa exc exe exi exp exp ext ext ext fac fal far fec Fer fer fie fin fir fis fla Flo flu fog for for Fou fra fre fre Fro fun G s Gal gal gal Gar gau geg gen geo geo geo ger gla gly gra gra gra gra gra Gre gro GYR Had Hal hap Har HD hea hel hel Hen Her hex hig Hil hol Hoo hor hou Hub hum hyb hyd hyd hyp hys ide ign ima imp imp in- inc Ind ind ine inf inf inf ini ins ins ins int int int int Int int int int inv ion iri irr iso iso iso Jea Jor jum K c Kep Ker kin kno lab Lam Lan Lap las lat Le lef len lev lig lig lin lin lin liq Lit loc log lon lou LS lun lun Lym M s Mag mag mag mag mag mag maj man Mar mas mas mat May mea mec mel mer mes met met met mic mid mil Min Mir mix mod mod mol mon mor mov mul mur mys nan nat nav nec Nep neu New New NGC nob nom non non nor nos nuc nuc num nut obj obl obs occ oct off oli oni ope opp opt opt orb ord org orp osc out ove oxi P-w pal par par par par Pas pat pej per per per per per per pha Phe pho pho pho phy pin pla Pla pla pla pla plu poi pol pol Pol pol por pos pot Poy pre pre pre pre pri pri pri pro pro pro pro pro pro Psa pul pum Q i qua qua qua qua R A rad rad rad rad rad rad Ram Ran rat rea rea rec rec red red ref ref reg rei rel rel rem rep res res res ret rev Rho Rie ril riv rog Ros rot rul S A Sag sam sat sca sca Sch Sco Sec sec sec seg sel sem sen set Sha sha shi sho sid sig sim sin Sir ske sli Smo soc sof sol sol sol sol sou sou spa spe spe Spe spe sph spi Spi spr sta sta sta sta sta ste ste ste Sto str str sub sub sub suc sun sup sup sup sup sur swa syn syn tac tas tel tem ter tes the the the the thi thr tid til tip ton tor tou tra tra tra tra Tri tri tru tsu tur two Typ UHE ult unc uni uni uni upg ura uti val var vec Vel ver Ver vie Vir vis vis vol W-R war wav wav wea Wei wha wid win WN3 Wol wri xen yok zen zij > >>