An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



<< < -en ear eav ecl edg EHB Ein ela ele ele ele ele ema emi Enc ene ens eph equ equ equ eru eth eur evo exa exc exi exo exp ext ext eye > >>

Number of Results: 644
oropiom (#)

Fr.: europium   

A ductile silvery-white metallic → chemical element; symbol Eu. → Atomic number 63; → atomic weight 151.96; → melting point about 820°C; → boiling point about 1,600°C; → specific gravity 5.25 at 25°C. Europium occurs in monazite and bastnaesite and is used to dope → lasers and to absorb → neutrons in research. It was separated from the mineral samaria in magnesium-samarium nitrate by the French chemist Eugène-Anatole Demarçay (1852-1904) in 1901.

Named after the continent Europe, → Europa.


Fr.: eutectique   

Mixture of two substances which solidifies as a whole when cooled, without change in composition. The eutectic point is the temperature at which the eutectic mixture solidifies.

From Gk. eutektos "easily melted," from → eu- + tektos "melted" + → -ic.

Hugodâz, from hu-, → eu-, + godâz, → melt.

âsânmiri (#)

Fr.: euthanasie   

The act or practice of putting painlessly to death, or allowing to die, especially in cases of incurable suffering.

From Gk. euthanasia "an easy or happy death," from → eu- "good" + thanatos "death."

Âsânmiri, literally "easy dyind," from âsân, → easy, + miri "dying," from mordan "to die," → death.

  ارزیابی کردن   
arzyâbi kardan (#)

Fr.: évaluer   

To determine or set the value or amount of; to judge or determine the significance, worth, or quality of.

Verbal form of → evaluation.

arzyâbi (#)

Fr.: évaluation   

An act or instance of evaluating; to examine and judge carefully.

From Fr. évaluer "to find the value of," from → ex- "out" + value "worth, value," p.p. of valoir "be worth," from L. valere "be strong, be of value;" PIE base *wal- "to be strong."

Arzyâbi, from arz "value" + yâbi "finding." The first component arz, present stem of 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." The second component yâbi, verbal noun of yâftan, yâbidan "to find, discover; to obtain, acquire;" Mid.Pers. ayâftan, ayâpênitan "to reach, attain;" Manichean Mid.Pers. 'y'b "to attain;" Parthian, Sogdian (+ *pati-) pty'b "to reach, obtain;" Av. ap- "to reach, overtake," apayeiti "achieved, reached;" Skt. âp- "to reach, gain," âpnoti "reaches, gains;" Gk. hapto, haptomai "to touch, cling to, adhere to;" L. apiscor "touch, reach;" PIE base *ap- "to take, reach."


Fr.: évanouir, disparaître   

To disappear gradually.



Fr.: évanescent   

Tending to → vanish gradually.

Verbal adj. from → evanesce.

evanescent wave
  موج ِ وننده   
mowj-e venandé

Fr.: onde évanescente   

A wave whose → amplitude → decreases → exponentially with distance from the → interface at which it is formed. Evanescent waves are formed when → sinusoidal waves are internally reflected off an interface at an angle greater than the → critical angle so that → total internal reflection occurs.

evanescent; → wave.

  بخاریدن؛ بخاراندن   
boxâridan; boxârândan

Fr.: évaporer   

(v.intr.) To change from liquid state into vapor; ( To convert into a gaseous state or vapor.

Verbal form of → evaporation.


Fr.: évaporation   

The physical process by which a liquid is transformed to the gaseous state, usually by means of heat; the opposite of → condensation. Also called vaporization.

From L. evaporationem (nom. evaporatio), from evaporare "to disperse in vapor," from → ex- "out" + → vapor "steam."

Boxârš, verbal noun of boxâridan "to evaporate," from boxâr, → vapor.


Fr.: évection   

A periodic perturbation in the motion of the → Moon caused by the variation in the gravitational pull of the Sun, which causes a change in the → eccentricity of the Moon's orbit during its monthly revolution. As a result, the Moon's → ecliptic longitude oscillates with a amplitude of ± 1°16' during a period of about 31.8 days.

From L. evection- "carrying away, going upwards, flight," from evect(us) p.p. of evehere "to carry forth, move forth," from e-, → ex- + vehere "to carry," cognate with Av. vaz- "to carry, move," as below.

Osbaz "carrying away," from os-, → ex-, + *baz "to carry," ultimately from Proto-Ir. *uaz- "to carry, drive;" from which Av. vaz- "to move, carry, drive (a chariot)," vazaiti "to lead;" Kurd. (Kurmanji) bazin/baz- "to run;" Mod./Mid.Pers. bazidan, vazidan "to blow (as the wind)," parvâz, → flight; cf. Skt. vah- "to ride, drive, transport;" Gk. oxos "carriage;" L. vehere "to carry;" Lith. veži "I ride;" O.H.G. wegan "to move, carry;" PIE base *wegh- "to go, carry, drive." See also: → advection; → convection.

even parity
  همالی ِ زوج   
hamâli-ye zowj

Fr.: parité paire   

A classical variable which does not change upon spatial inversion, such as time, energy, angular momentum and so on. → odd parity.

Even, from O.E. efen "level; equal," from P.Gmc. *ebnaz (cf. Ger. eben; Goth. ibns); → parity.

Hamâli, → parity; zowj "pair, couple; an even number," from Ar.

  ایوار، شامگاه   
ivâr (#), šâmgâh (#)

Fr.: soir, soirée   

The latter part of the → day and early part of the → night. Not an astronomical term proper. → evening star.

From O.E. verb æfnung "to grow toward evening," from æfnian "to become evening," from æfen "evening," from P.Gmc. *æbando- (cf. O.H.G. aband, Ger. abend).

Ivâr "evening" (Lori, Laki êvâra; Borujerdi ivâra; Kurd. ewâra); Mid.Pers. êvârak "evening;" šâmgâh, from šâm "evening, evening meal" + gâh "time." The first component, šâm, from Mid.Pers. šâm "evening meal, supper," from Av. xšāfnya- "evening meal," from Av. xšap-, xšapā-, xšapan-, xšafn- "night" (O.Pers. xšap- "night;" Mid.Pers. šap; Mod.Pers. šab "night"); cf. Skt. ksap- "nigh, darkness;" Hitt. ispant- "night." The second component gâh "time;" Mid.Pers. gâh, gâs "time;" O.Pers. gāθu-; Av. gātav-, gātu- "place, throne, spot;" cf. Skt. gâtu- "going, motion; free space for moving; place of abode;" PIE *gwem- "to go, come."

evening star
  ستاره‌ی ِ شامگاه   
setâre-ye šâmgâh (#)

Fr.: étoile du soir   

Any bright → planet, often → Venus, seen low in the western sky after → sunset. → Hesperus.

evening; → star.

ruydâd (#)

Fr.: événement   

1) General: Something that happens or is regarded as happening; an occurrence, especially one of some importance.
2) Einstein's relativity: An occurrence in the → space-time continuum referenced by three spatial coordinates and a complementary temporal ordinate. → world line; → space-time diagram.
3) Statistics: A subset of the → sample space.

From M.Fr. event, from L. eventus "occurrence, issue," from evenire "to come out, happen, result," from → ex- "out" + venire "to come," from PIE base *gwem- "to go, come;" cf. Mod/Mid.Pers. gâm "step, pace;" O.Pers. gam- "to come; to go;" Av. gam- "to come; to go," jamaiti "goes;" 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.

Ruydâd, noun from ruy dâdan "to occur, happen," originally "to appear," from ruy "face; aspect; appearance" (Mid.Pers. rôy, rôdh "face;" Av. raoδa- "growth," in plural "appearance," from raod- "to grow, sprout, shoot;" cf. Skt. róha- "rising, height") + dâdan "to give; to command" (Mid.Pers. dâdan "to give;" O.Pers./Av. dā- "to give, grant, yield," dadāiti "he gives;" cf. Skt. dadáti "he gives;" Gk. didomi "I give;" L. dare "to give, offer," facere to make;" PIE base *do- to give").

event horizon
  افق ِ رویداد   
ofoq-e ruydâd (#)

Fr.: horizon d'événement   

1) The surface surrounding a → black hole with the property that any light ray emitted inside it cannot escape to the outer space because of the strength of the → gravitational field. The radius of the event horizon is called the → Schwarzschild radius. See also → photon sphere.
2) For an observer A at the instant t0, the surface in the → space-time that divides the collection of all events into two non-empty classes: those events that have been, are being, or will be observed by A, and those that A has never observed and will never be able to observe (J. Plebanski, A. Krasinski, 2006, An Introduction to General Relativity and Cosmology, Cambridge Univ. Press).

event; → horizon.

ever-expanding Universe
  گیتی ِ هماره‌گسترا   
giti-ye hamâré gostarâ

Fr.: Univers en expansion continue   

Same as → accelerating Universe.

expand; → Universe.


Fr.: évidence, preuve   

That which tends to prove or disprove something; something that makes plain or clear.

Noun form of → evident.

Âvišé, from âviš, → evident + noun suffix , Mid.Pers. -ak/-ag.


Fr.: évident   

Plain or clear to the sight or understanding.

From L. evidentem (nom. evidens) "perceptible, obvious," from → ex- "fully, out of" + videntem (nom. videns), pr.p. of videre "to see," from PIE base *weid- "to know, to see;" cf. Mod.Pers. bin- "to see" (present stem of didan); Mid.Pers. wyn-; O.Pers. vain- "to see;" Av. vaēn- "to see;" Skt. veda "I know;" Gk. oida "I know," idein "to see;" O.E. witan "to know;" Goth. weitan "to see;" E. wise; Ger. wissen "to know;" Lith. vysti "to see;" Rus. videt' "to see," vest' "news."

Âviš, from Av. āviš, āuuiš "evidently, before the eyes," āuuišiia- "manifest;" Mid.Pers. âškârâg "manifest;" Mod.Pers. âškâr (Proto-Iranian *āuiš-kâr); Arm. loanword from Iranian aškaray "open, not hidden;" cf. Skt. āvis "evidently, before the eyes;" O.C.S. (j)avé "manifest, known" (loanword from Iranian); L. audire "to hear;" Gk. aisthanesthai "to feel."


Fr.: évocation   

The act or fact of evoking.

Verbal noun of → evoke.

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