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 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
zero matrix
  ماتریس ِ صفر   
mâtris-e zefr

Fr.: matrice nulle   

Same as → null matrix.

zero; → matrix.

zero method
  روش ِ صفر   
raveš-e sefr

Fr.: méthode de zéro   

same as → null method.

zero; → method.

zero point
  نقطه‌ی ِ صفر   
noqte-ye sefr

Fr.: point zéro   

1) General: A starting point for making a measurement.
2) A basic parameter on which a → photometric system relies and must be determined each night. The zero points of → magnitudes and color indices (→ color index) depend on atmospheric transparency that varies from night to night.

zero; → point.

zero point energy
  کاروژ ِ نقطه‌ی ِ صفر   
kâruž-e noqte-ye sefr

Fr.: énergie du point zéro, point zéro   

The lowest possible energy that a → quantum mechanical system may possess. It is the energy of the → ground state of the system. The term "zero point" refers to the observed fact that → vacuum fluctuations persist at → absolute zero temperature. Same as → vacuum energy.

zero; → point; → energy.

zero polynomial
  بلنامین ِ صفر   
bolnâmin-e sefr

Fr.: polynôme nul   

A → polynomial whose → coefficients are all zero. See also → non-zero polynomial.

zero; → polynomial.

zero suppression
  نهاوش ِ صفر   
nehâveš-e sefr

Fr.: suppression de zéro   

The removal of non-significant zeroes from a number. For example, replacing 531.2300 by 531.23.

zero; → suppression.

zero-velocity surface
  رویه‌ی ِ تندای ِ صفر   
ruye-ye tondâ-ye sefr

Fr.: surface de vitesse nulle   

In the → restricted three-body problem, a surface which limits the region of space in which a small body can move. In the expression for the → Jacobi integral, the left side value is always positive or nul; hence the particle motion is confined to the region where U ≤ CJ. The surface that limits this region, defined by U = CJ, is called the zero-velocity surface.

zero; → velocity; → surface.

zeroth law of thermodynamics
  قانون ِ صفرُم ِ گرماتوانیک   
qânun-e sefrom-e garmâtavânik

Fr.: loi zéro de la thermodynamique   

Two objects that are in → thermal equilibrium with a third object will be in thermal equilibrium with each other.

zero; → law; → thermodynamics.

Zeta Ophiuchi
  زتا-مار‌افسا   
Zetâ Mâr-afsâ

Fr.: ζ Ophiuchi   

A blue star, also called HD 149757 and HR 6175, which is the nearest, and probably the most widely studied, → massive star. It is variable in several wavelength bands and has a mean visual magnitude of V = 2.58, B - V = 0.01. It lies ~ 222 pc away and has a formal spectral type of O9.5 Ve and a luminosity of 105 Lsun. ζ Ophiuchi is a very rapid rotator with a v sin i ~ 400 km s-1, i.e. ~ 85% of the → break-up velocity. It is one of the earliest prototypes of the → Be phenomenon. Moreover, it shows episodes of Hα emission variability, a common feature of Be/Oe stars. It also shows periodic non-radial pulsations and UV → P Cygni profile variability, as is evident in the periodic behavior of → discrete absorption components (DACs). It has a → mass loss rate of 10-7 Msun yr-1 and a → terminal velocity of wind v = 1550 km s-1. ζ Ophiuchi is a well-known → runaway star with a velocity of 30 km s-1. The interstellar → CH molecule and → CN molecule were first detected toward ζ Ophiuchi. It has been recognized for some time that this star lies close to the blue edge of the → beta Cephei instability strip.

Zeta (ζ), according to the → variable star designation system; Ophiuchi, → Ophiuchus.

Zeta Orionis
  زتا-شکارگر، زتا-اریون   
zetâ-Šekârgar, zetâ-Orion

Fr.: Zeta (ζ) Orionis   

Same as → Alnitak.

Zeta (ζ), Gk. letter in the → Bayer designation scheme.

zetta-
  زتا-   
zetta-

Fr.: zetta-   

A prefix of the → SI units, denoting 1021. Symbol: Z.

From L. septem, → hepta-, by replacing the initial s with z to distinguish from → zepto-. It is equal to 10007.

Zhevakin's zone
  زنار ِ ژواکین   
zonaar-e Zhavakin

Fr.: zone de Zhevakin   

One of several regions of the stellar interior where increased → opacity can provide the necessary → valve mechanism to drive → stellar pulsations. Also called → partial ionization zone.

Named after the Russian astronomer Sergei A. Zhevakin (1916-2001), who identified these zone in the 1950s; → mechanism.

zij
  زیج   
zij (#)

Fr.: zij   

The generic name applied to books in Arabic and Persian that tabulate parameters used for astronomical calculations of positions of the Sun, the Moon, and the five planets of antiquity. Some examples: Zij al-Sindhind, by Khwarizmi (c. 780-850), Az-Zij as-Sabi by al-Battâni (Albatenius) (853-929), Zij-i Ilkhâni by Nassireddin Tusi (1201-1274), Zij-i Sultâni by Ulugh Brg (1437), → Toledan Tables, → Alfonsine Tables.

The word is derived from Mid.Pers. zig, variant zih "cord, string" (Mod.Pers. zeh "cord, string"); Av. jiiā- "bow-string," cognate with Skt. jiyā- "bow-string," PIE base *gwhi- "thread, tendon" (from which derive also Gk. bios "bow", L. filum "thread", Russ. žca "thread").
The term zig originally referred to the threads in weaving, but because of the similarity between the rows and columns of astronomical tables and the parallel threads, it came to be used for an astronomical table, and subsequently a set of tables.

zinc
  روی   
ruy (#)

Fr.: zinc   

A metallic, lustrous, bluish-white → chemical element; symbol Zn. → Atomic number 30; → atomic weight 65.38; → melting point 419.58 °C; → boiling point 907 °C; → specific gravity 7.133 at 25 °C. It was recognized as a → metal as early as 1374.

From the Ger. Zink of unknown origin. Zinc compounds were known in prehistoric times, where they were used for healing wounds and for making brass.

Ruy, from Mid.Pers. rôy, rôd "copper, brass;" Av. raoiδita- "red, reddish;" cf. Skt. rohita- "red, reddish," lohá- "red, reddish, reddish metal."

zircon
  زرگون   
zargun (#)

Fr.: zircon   

A common mineral, zirconium silicate, ZrSiO4, occurring in small tetragonal crystals. The color is variable, usually brown to reddish brown, but also colorless, pale yellowish, green, or blue. A red variety, used as a gem, is called hyacinth. Zircon contains trace amounts of uranium and thorium and therefore can be used for radiometric datings. Also called jargon.

From Ger. Zirkon, from Ar. zarqun "cinnabar, bright red," from Pers. zargun "gold-colored," from zargold + -gun "resembling; manner, fashion; color" (Mid.Pers. gônak "kind, species;" Av. gaona- "color").

zirconium
  زیرکونیوم   
zirkoniom (#)

Fr.: zirconium   

A metallic chemical element; symbol Zr. Atomic number 40; atomic weight 91.22; melting point about 1,852°C; boiling point 4,377°C; specific gravity 6.5 at 20°C. Zirconium was discovered in the mineral zirconia by the German chemist Martin-Heinrich Klaproth in 1789. It was first isolated by the Swedish chemist Jons Jacob Berzelius in 1824 in an impure state and finally by the chemists D. Lely Jr. and L. Hamburger in a pure state in 1914.

From → zircon.

zirconium oxide, ZrO
  اکسید ِ زیرکونیوم   
oksid-e zirkoniom

Fr.: oxide de zirconium   

A → diatomic molecule made up of → zirconium and → oxygen atoms. See → ZrO band.

zirconium; → band.

zodiac
  برجگان، برج زنار   
borjgân

Fr.: zodiaque   

An imaginary belt around the heavens extending about 9° on either side of the → ecliptic. The orbits of the Moon and of the principal planets also lie entirely within the zodiac. The zodiac was created during the first half of the first millennium B.C. by Babylonian astronomers, who divided it into 12 constellations (→ sign of the zodiac) each considered to occupy 1/12, or 30°, of its great circle. They were named after living creatures, with the exception of Libra: → Aries, → Taurus, → Gemini, → Cancer, → Leo, → Virgo, → Libra, → Scorpius, → Sagittarius, → Capricornus, → Aquarius, → Pisces. However, as a result of → precession, these signs no longer correspond to the astronomical constellations in which the Sun actually appears. The constellations are irregular in size and shape, and the Sun regularly passes through 13 constellations as it moves along the ecliptic. The additional 13th constellation is → Ophiuchus, situated between → Scorpius and → Sagittarius. See also → dodekatemorion.

From M.E. zodiaque, from O.Fr. zodiaque, from L. zodiacus, from Gk. zodiakos (kyklos) "zodiac (circle)," literally "circle of little animals," from zodiaion, diminutive of zoion "animal," literally "a living being," from PIE base *gwei- "to live, life;" cognate with Pers. zist, → bio-.

Borjgân, from borj, → sign of the zodiac, + -gân suffix denoting multiplicity, order, organization.

zodiacal
  برجگانی   
borjgâni

Fr.: zodiacal   

Of or relating to the → zodiac.

zodiac; → -al.

zodiacal belt
  کمربند ِ برجگانی، زنار ِ ~   
kamarband-e borjgâni, zonâr-e ~

Fr.: ceinture zodiacale   

zodiac.

zodiacal; → belt.

<< < -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 > >>