An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



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Number of Results: 491
do- (#)

Fr.: bi-   

Prefix denoting "two, both, twice."

From L. bi-, cognate of Gk. di-, O.E. twi-; cf. Av. bi- "two," biš "twice," Mod.Pers. do "two," PIE *dwo- "two."

Do, Mid.Pers. do, Av. dva-, Skt. dvi-, Gk. duo, L. duo, E. two, Ger. zwei, Fr. deux.

Bianchi cosmological model
  مدل ِ کیهانشناختی ِ بیانکی   
model-e keyhânšenâxti-ye Bianchi

Fr.: modèle cosmologique de Bianchi   

A cosmological model based on the theory of → general relativity, which is homogeneous but → anisotropic. There are actually ten dinstinct Bianchi types, classified according to the particular kinds of symmetry they posses.

Luigi Bianchi (1856-1928), Italian mathematician; → cosmological; → model.

  ۱) ورک؛ ۲) پیش-تنش؛ ۳) ورک دادن   
1) varak; 2) pištaneš; 3) varak dâdan

Fr.: 1, 2) biais; 3) biaiser   

1) General: Leaning of the mind toward or away from something; especially: a personal and sometimes unreasoned judgment.
Statistics: A → systematic error introduced by selecting items from a wrong population, favoring some of the elements of a population, or poorly phrasing questions.
2) Electronics: A → voltage applied to a device to establish a reference level for operation. Same as initial voltage, initial tension (Ger. die Vorspannung). In a → CCD detector, electronic → offset which prevents negative signal.
3a) General: To give a settled and often prejudiced outlook to.
3b) Electronics: To apply a small voltage to a device to control its operation. See also: → bias error, → bias frame, → bias offset, → bias voltage, → biased, → biased estimate, → biased galaxy formation, → biased sample, → biased statistics, → debias, → kinematic bias, → Lutz-Kelker bias, → Malmquist bias, → observational bias, → sampling bias, → unbiased, → unbiased estimator.

From M.Fr. biais "slant," perhaps ultimately from Gk. epikarsios "slanting, oblique," from epi- "upon" + karsios "oblique."

Varak, from var "side, direction" + -ak suffix denoting relation, affinity, similarity (as in dastak, poštak, pašmak, xarak, nâxonak, mušak, eynak). Note also var in yekvar "slanting, inclined".
Pištaneš, only in the electronic sense, from piš, → pre- + taneš, → tension.
Varak dâdan, from varak + dâdan "to give," → datum.

bias error
  ایرنگ ِ ورک، خطای ~   
irang-e varak, xatâ-ye ~

Fr.: erreur de biais   

A measurement error that remains constant in magnitude for all observations; for example an incorrectly set zero adjustment.

bias; → error.

bias frame
  نورداد برای ِ ورک   
nurdâd barây-e varak

Fr.: pose pour biais   

CCD frame with exposure time set to zero and giving the bias level.

bias; → frame.

Nurdâd, → exposure; varakbias

bias offset
  اپنه ِ ورک   
apneh-e varak

Fr.: biais   

In → CCD detectors, same as → bias and → offset.

bias; → offset.

bias voltage
  ولتاژ ِ ورک   
voltâž-e varak

Fr.: voltage de biais   

A voltage applied or developed between two electrodes as a bias.

bias; → voltage.


Fr.: biaisé   

Marked by or exhibiting bias; characterized by settled and often prejudiced outlook.

Biased, from → bias + adj. suffix -ed.

Varakdâr, from varak, → bias + -dâr "possessing, having," from dâštan "to possess, to have."

biased estimate
  بر‌آورد ِ ورکدار   
barâvard-e varakdâr

Fr.: estimation biasiée   

Of a population parameter, if the mean or expectation of the statistics is not equal to the parameter.

biased; → estimate.

barâvard, → estimate; varakdârbiased.

biased galaxy formation
  دیسش ِ ورکدار ِ کهکشانها   
diseš-e varakdâr-e kahkašânhâ

Fr.: formation biaisée de galaxies   

The theory that bright galaxies form preferentially from anomalously overdense perturbations in the → early Universe.

biased; → galaxy; → formation.

biased sample
  نمونان ِ ورکدار   
nemunân-e varakdâr

Fr.: échantillon biaisé   

A sample that is not a true representative of a → statistical population to which generalizations are to be made. A sample which is not → randomly constituted.

biased; → sample.

biased statistics
  آمار ِ ورکدار   
âmâr-e varakdâr

Fr.: statistique biasée   

A statistics based on a → biased sample.

biased; → statistics.

biaxial crystal
  بلور ِ دو‌آسه   
bolur-e doâsé

Fr.: cristal biaxe   

A birefrigent crystal, such as mica, that is characterized by having two optical axes along which light is propagated with equal velocities.

Biaxial, from → bi- "two" + axial, from → axe; → crystal.


Fr.: BICEP2   

A → microwave → polarimeter designed specifically to target the → B-mode signature of → inflation in the → cosmic microwave background polarization. BICEP2 observed from the South Pole for three seasons from 2010 to 2012. This 26 cm aperture → telescope comprised an all-cold refracting optical system equipped with a → bolometer array of 512 → detectors (256 pixels) operating at 150 GHz.

BICEP2, the upgraded version of the first BICEP, short for Background Imaging of Cosmic Extragalactic Polarization.

biconcave lens
  عدسی ِ دوکاو   
adasi-ye dokâv

Fr.: lentille biconcave   

Describing a lens with two concave faces.

Biconcave, from → bi- + → concave; → lens.

Adasi, → lens; dokâv "biconcave," from do-, → bi- + kâv, → concave.

biconvex lens
  عدسی ِ دوکوژ   
adasi-ye dokuž

Fr.: lentille biconvexe   

A spherical lens with two convex faces. The radii of curvature for the two surfaces may or may not be the same.

Biconvex, from → bi- + → convex; → lens.

Adasi, → lens; dokuž "biconvex" from do-, → bi- + kuž, → convex.

Biela's comet
  دنباله‌دار ِ بیلا   
donbâledâr-e Biyelâ

Fr.: comète de Biela   

A comet having a short period of 6.62 years discovered by Biela. It broke up on its 1846 return and subsequently gave rise to a spectacular meteor shower.

In honor of Wilhelm von Biela (1782-1856), Austrian military officer and amateur astronomer, who re-discovered the comet Biela in 1826, although it had been seen first in 1772. → comet.


Fr.: Bielides   

A → meteor shower, originating from → Biela's comet, whose → radiant lies in the constellation → Andromeda; also called → Andromidids.

Bielids, From Biel(a) + → -ids suffix denoting "descendant of, belonging to the family of."

  ۱) دوگلیدن؛ ۲) دوگل   
1) dogalidan; 2) dogal

Fr.: 1) bifurquer; 2) à deux branches   

1) To divide into two branches.
2) Divided into two branches.

M.L. bifurcatus, from L. → bi- "two," + furca "pitchfork; fork used in cooking," of uncertain origin.

Dogalidan, from Gilaki dogal "fork, two-branched," cf. Tabari dekal, dokkal, doqâla, from do, → two, + gal, kal "branch, part," cf. Kurd. (Kurmanji) kar "part, piece," cognate with Pers. kârd "knife," (+ *niš-) nišgarda "cobbler's knife;" Mid.Pers. kârt "knife," karēnītan, karītan "to cut," (+ *fra-) fragard "chapter, section;" Av. karət- "to cut;" Proto-Iranian *kart- "to cut;" cf. Skt. kart- "to cut;" Gk. karpos "fruit;" L. carpere "to cut, divide, pluck;" PIE base *(s)ker- "to cut;" + -idan infinitive suffix. See also → shear.


Fr.: bifurcation   

1) A branching or division into two parts; a splitting apart.
2) A sudden qualitative change in the behavior of a → dynamical system. The equation describing the evolution of the system finds several solutions for certain values of a parameter. Systems undergoing a bifurcation do not necessarily return to their original state, even if the parameter returns to its nominal value. See also → chaos.

Verbal noun of → bifurcate.

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