An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



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Number of Results: 146
farâzâb (#)

Fr.: en amont   

1) Toward or in the higher part of a stream; against the current. → downstream
2) Directed upstream; situated upstream.

up; → stream.

Farâz, → height; water, → water.

urâniyom (#)

Fr.: uranium   

A radioactive metallic chemical element; symbol U. Atomic number 92; atomic weight 238.0289; melting point 1,132°C; boiling point 3,818°C; specific gravity 19.1 at 25°C. A radioactive element with 14 known isotopes of which 238U is the most abundant in nature. This isotope (half-life 4.5 billion years) is 138 times more abundant than 235U (half-life 710 million years). The metal was first isolated by the French chemist Eugène-Melchior Peligot in 1841.

From the name of the planet → Uranus. The German chemist Martin-Heinrich Klaproth discovered the element in 1789, following the German/English astronomer William Hershel's discovery of the planet in 1781.

uranium hexafluoride
  هگزافلویءورید ِ اورانیوم   
hegzâfluorid-e urâniyom

Fr.: hexafluorure d'uranium   

A white solid compound of → uranium and → fluorine obtained by chemical treatment of U3O8 (yellow cake), forming a vapor at temperatures above 56°C. It contains both of the naturally occurring isotopes of uranium U-235 and U-238. The isotopes are separated on the basis of differences in their diffusion properties.

uranium; → hexa-; → fluoride.

Urânus (#)

Fr.: Uranus   

The seventh planet from the Sun and the third largest, discovered by William Herschel in 1781. It has a diameter about 51,100 km, four times that of the Earth, and a mass 14.5 times Earth's mass. Uranus orbits the Sun at a distance over 19 times the Earth-Sun distance. Although it takes about 84 years for Uranus to make a revolution, it completes a fast rotation in only 17 and a half hours. Unlike the other planets, its axis of rotation lies mostly in the plane of the Solar System. Uranus is internally less active than the other giant planets, which added to its larger distance from the Sun, makes it colder. It has a dense atmosphere made of mostly molecular hydrogen (83 percent) and helium (15 percent), with two percent methane and traces of acetylene and other hydrocarbons. The planet's greenish-blue color is due to light scattering as in Earth's sky and the absorption of red light by its small amount of atmospheric methane. Uranus has a ring system and 27 known satellites.

L. Uranus, from Gk. Ouranos "heaven." In Gk. mythology he was the the primeval sky god, and responsible for both the sunshine and the rain. He was the son and husband of Gaia, the goddess of the Earth and the father of Titans.

Urca process
  فراروند ِ اورکا   
farâravand-e Urkâ

Fr.: processus Urca   

A cycle of nuclear reactions, primarily among the iron group of elements, accompanied by a high rate of neutrino formation. Neutrinos carry away energy quickly leading to the cooling of the stellar core and a dramatic drop in the pressure. Due to this process in pre-supernova stars, the core becomes unable to support the weight of the overlying layers. These layers collapse onto the core and subsequently rebound and escape in the supernova explosion.

Named for the de Urca Casino in Rio de Janeiro, by George Gamow and Mario Schönberg, who first studied this process. Gamow is reported to have pointed to the similarity between the disappearance of money in the crowded gambling rooms of the Casino and the disappearance of electron energy into invisible neutrinos; → process.

  ۱) گرژیدن؛ ۲) گرژ   
1) garžidan; 2) garž

Fr.: 1) pousser, exhorter, presser; 2) désir ardent, forte envie   

1a) To push or force along; impel with force or vigor.
1b) To drive with incitement to speed or effort.
1c) To impel, constrain, or move to some action.
2) An act of urging; impelling action, influence, or force; impulse (

From L. urgere "to press hard, push forward, drive, compel,," from PIE root *ureg- "to push, shove, drive;" cf. Lith. verziu "tie, fasten, squeeze," vargas "need, distress;" O.C.S. vragu "enemy;" Gothic wrikan "to persecute;" O.E. wrecan "avenge; drive, hunt, pursue;" E. wreak "to inflict, to cause;" Av. uruuaj- "to walk," see below.

Garžidan, from Proto-Ir. *uraj- "to go forth" (Cheung 2007; on the model of *urad- "to soften," Baluchi grast "to cook in oil or water"); cf. Av. uruuaj- "to go forth, walk;" cf. Kurd. guš, gušin (?) "to press, squeeze, shake;" Skt. vraj- "to stride, walk, proceed;" cognate with L. urgere, as above (Cheung 2007).

  گرژانش، گرژانی   
garžâneš, garžâni

Fr.: urgence   

The quality or state of being urgent; imperativeness; insistence.

Noun from → urgent.


Fr.: urgent   

Compelling or requiring immediate action or attention; imperative; pressing (

Adj. from → urge.

Ursa Major
  خرس ِ بزرگ   
Xers-e Bozorg (#)

Fr.: Grande Ourse   

The Great Bear. An extensive and prominent constellation in the region of the north celestial pole, at approximately 10h 40m right ascension, +56° declination. The seven brightest stars of Ursa Major are known as the → Big Dipper. The region contains the planetary → Owl Nebula and the spiral galaxies M81 and M82. Abbreviation: UMa, Genitive: Ursae Majoris.

Ursa,from L. ursus "bear," cognate with Pers. xers, as below; Major irregular comparative adj. of magnus "large, great," cognate with Pers. meh "great, large" (Mid.Pers. meh, mas; Av. maz-, masan-, mazant- "great, important," mazan- "greatness, majesty," mazišta- "greatest;" cf. Skt. mah-, mahant-; Gk. megas; PIE *meg- "great").

In Gk. mythology, Zeus falls in love with the nymph Callisto, and they have a son named Arcus. To hide Callisto from the wrath of his wife, Hera, Zeus changed her into a bear. Later on, when Arcus saw the bear Callisto, drew his bow and prepared to shoot her. To prevent Arcus from killing his mother, Zeus placed them together in the sky as the Big Bear and the Little Bear.

Xers "bear," dialectal Tabari ; Mid.Pers. xirs, Av. arša- "bear;" cf. Skt. rksa- "bear;" Gk. arktos; L. ursus; PIE base *rtko- "bear;" bozorg "large, magnificient, great;" Mid.Pers. vazurg "great, big, high, lofty;" O.Pers. vazarka- "great;" Av. vazra- "club, mace" (Mod.Pers. gorz "mace"); cf. Skt. vájra- "(Indra's) thunderbolt," vaja- "strength, speed;" L. vigere "be lively, thrive," velox "fast, lively," vegere "to enliven," vigil "watchful, awake;" P.Gmc. *waken (Du. waken; O.H.G. wahhen; Ger. wachen "to be awake;" E. wake); PIE base *weg- "to be strong, be lively."

Ursa Major cluster
  خوشه‌ی ِ خرس ِ بزرگ   
xuše-ye Xers-e Bozorg (#)

Fr.: amas de la Grande Ourse   

A moving star cluster containing over 100 stars that are scattered over an area of sky more than 1000 minutes of arc in diameter. The five brightest stars of the → Big Dipper as well as → Sirius belong to this cluster.

Ursa Major; → cluster.

Ursa Minor
  خرس ِ کوچک   
Xers-e Kucak (#)

Fr.: Petite Ourse   

The Lesser Bear. A constellation situated in the northern hemisphere, at about 15h right ascension, +79° declination. Its two brightest stars, both of 2nd magnitude, are → Polaris, the present pole star, and → Kochab. Abbreviation: UMi, Genitive: Ursae Minoris.

Ursa,from L. ursus "bear," cognate with Pers. xers, as below; Minor "smaller, less," from minus related to L. minuere "make small;" cf. Gk. meion "less," minuthein "to lessen;" Skt. miyate "diminishes, declines;" O.E. minsian "to diminish;" PIE base *mei- "small."

Xers "bear," dialectal Tabari ; Mid.Pers. xirs, Av. arša- "bear;" cf. Skt. rksa- "bear;" Gk. arktos; L. ursus; PIE base *rtko- "bear;" kucak "small;" Mid.Pers. kucak "small," related to kutâh "short, small, little," kudak "child, infant," kutulé, → dwarf; Mid.Pers. kôtâh "low," kôtak "small, young; baby;" Av. kutaka- "little, small."

Ursa Minor system
  راژمان ِ خرس ِ کوچک   
râžmân-e Xers-e Kucak

Fr.: galaxie naine d'Ursa Minor   

A dwarf spheroidal galaxy of faint luminosity that is a member of the Local Group.

Ursa Minor; → system.


Fr.: Urvara   

An → impact cratrer on → Ceres which is the third largest crater on this → dwarf planet. Urvara is located south of → Occator and is about 160 km wide and 6 km deep. It has a prominent central peak that is about 3 km high.

Named for the ancient Indo-Iranian personification of fertility, Av. urvarā- "plant," often defied, Skt. urvárā- "land, soil, fertile field."

kârbar (#)

Fr.: utilisateur   

A person who uses or exploits something, such as a computer.

From use; M.E. usen from O.Fr. user "to use, employ," from V.L. *usare "to use," from L. uti "to use."

Kârbar "user," from bé kâr bordan "to use."

users committee
  کمیته‌ی ِ کاربران   
komite-ye kârbarân

Fr.: comité des utilisateurs   

A committee whose members represent the astronomers who use the facilities of an observatory and which is intended to improve the interaction between the observatory and the users.

user; committee, M.E., from O.Fr. commettre "to commit," from L. committere "to bring together," from → com- + mittere "to put, send."

Komité, loan from Fr.; kârbarân plural of kârbaruser.


Fr.: utilitaire   

1) Of, relating to, or in the interests of utility.
2) Of, characterized by, or adhering to → utilitarianism.

Coined by Jeremy Bentham (1748-1832) from → utility + -arian.

  هوده‌مندی‌باوری، هوده‌مندی‌گرایی   
hudemandibâvari, hudemandigerâyi

Fr.: utilitarisme   

Philosophy: A doctrine according to which the virtue of a thing or an action is determined by its utility. The goal of utilitarian ethics is to promote the greatest happiness for the greatest number of people. The founders of this philosophical school were Jeremy Bentham (1748-1832) and James Mill (1773-1836).

utilitarian; → -ism.

  ۱) هوده‌مندی؛ ۲) هوده‌مند   
1) hudemandi; 2) hudemand

Fr.: 1) utilité; 2) utilitaire   

1) The state or quality of being useful; usefulness.
2) Having, or made for, useful practical purposes. → utility software.

M.E. utilite, from O.Fr. utilite "usefulness," earlier utilitet, from L. utilitatem "usefulness, profit," from utilis "usable," from uti "to use."

Hudemandi, from hudemand "utile," from hudé "use" (as in bihudé "useless, vain, absurd"), from Mid.Pers. hudâg "good, useful, beneficent;" Av. hūdā- "doing good, producing wealth," from hū-, hu-, → eu-, + Av./O.pers. dā- "to give, grant, put," dadāiti "he gives;" Mid.Pers./Mod.Pers. dâdan "to give, put" (cf. Skt. dadáti "he gives;" Gk. tithenai "to place, put, set," didomi "I give;" L. dare "to give, offer;" Rus. delat' "to do;" O.H.G. tuon, Ger. tun, O.E. don "to do;" PIE base *dhe- "to put, to do") + -mand(i)

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.


Fr.: utilisation   

The act or process of utilizing.

Verbal noun of → utilize.

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