An Etymological Dictionary of Astronomy and Astrophysics
English-French-Persian

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory

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Number of Results: 1965 Search : ion
equation of time
  هموگش ِ زمان   
hamugeš-e zamân

Fr.: équation du temps   

The difference, due to Earth's elliptical orbit and variable orbital velocity, between apparent solar time and mean solar time. It varies throughout the year, and slightly from year to year. At present, it reaches extremes of about -14 minutes in February, and about +16 minutes in November. The equation of time is visually illustrated by an → analemma.

equation; → time.

equilibrium partitioning
  پرکه‌بندی ِ ترازمند   
parkebandi-ye tarâzmand

Fr.: équilibre de partition   

A concept whereby chemical → concentrations among geological or environmental media are at equilibrium, and therefore the partitioning of metals in those media can be predicted based on → partition ratios.

equilibrium; → partitioning.

equilibrium position
  نهش ِ ترازمندی   
naheš-e tarâzmandi (#)

Fr.: position d'équilibre   

The position of an oscillating body at which no net force acts on it.

equilibrium; → position.

equipartition of energy
  هموگپرکش ِ کاروژ   
hamugparkeš-e kâruž

Fr.: équipartition de l'énergie   

1) General: Equal sharing of the → total energy among all → components of a → system.
2) In the → kinetic theory of gases, the → theorem according to which → molecules in → thermal equilibrium have the same average energy (1/2 kT) associated with each independent → degree of freedom of their motion.

equi-; → partition.

equivalent positions
  نهش‌های ِ هموگ‌ارز   
nehešhâ-ye hamug-arz

Fr.:   

Complete set of points in any given space group which are obtained by performing the symmetry operations of the space group on a single point (x, y, z).

equivalent; → position.

erosion
  فرسایش   
farsâyeš (#)

Fr.: érosion   

Geology: The act or state of eroding; state of being eroded.
A general term applied to the wearing away and movement of earth materials by the action of water, glaciers, winds, gravity, etc.

From M.Fr. erosion, from L. erosionem (nom. erosio), from erodere "to gnaw away," from → ex- "away" + rodere "to gnaw, eat away" (cf. Fr. and E. animal rat).

Farsâyeš, from far- intensive prefix "much, abundant" (Mid.Pers. fra- "forward, before; much; around;" O.Pers. fra- "forward, forth;" Av. frā, fərā-, fra- "forward, forth; excessive;" cf. Skt. prá- "before; forward, in fron;" Gk. pro "before, in front of;" L. pro "on behalf of, in place of, before, for;" PIE *pro-) + verbal noun of sâyidan, variants sâbidan "to bruise, file," pasâvidan "to touch;" Khotanese sauy- "to rub;" Sogdian ps'w- "to touch;" Proto-Iranian *sau- "to rub."

eruption
  اسدرش   
osdareš

Fr.: éruption   

1) An act, process, or instance of erupting; something that is erupted or ejected.
2) → flare.
3) Geology: The ejection of molten rock, steam, etc., as from a volcano or geyser.

Verbal noun of → erupt.

estimation
  بر‌آوری   
barâvari (#)

Fr.: estimation   

Statistics: The process by which sample data are used to indicate the value of an unknown quantity in a population.

Verbal noun of → estimate.

Euclidean division
  بخش ِ اقلیدوسی   
baxš-e Oqlidosi

Fr.: division euclidienne   

In arithmetic, the conventional process of division of two → integers. For a → real number a divided by b > 0, there exists a unique integer q and a real number r, 0 ≤ r <b, such that a = qb + r.

Euclidean; → division.

Euler equation
  هموگش ِ اویلر   
hamugeš-e Euler

Fr.: équation d'Euler   

In → fluid mechanics, one of a set of → differential equations that govern the motion of a → compressible, → inviscid fluid. Euler equations correspond to the → Navier-Stokes equations with zero → viscosity.

Euler; → equation.

evaluation
  ارزیابی   
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."

evaporation
  بخارش   
boxâreš

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.

evection
  اسبز   
osbaz

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.

evocation
  زاوچ   
zâvac

Fr.: évocation   

The act or fact of evoking.

Verbal noun of → evoke.

evolution
  فرگشت   
fargašt (#)

Fr.: évolution   

Any process of formation or growth; development; a process of gradual, progressive change; a product of such development; something evolved.
Astro.: A continuous and progressive change according to certain laws and by means of acting physical forces.
Biology: A process of development in which a living organism, through major environmental changes, becomes more and more complex by the differentiation of its parts.

Verbal noun of → evolve.

evolutionary
  فرگشتی   
fargašti (#)

Fr.: évolutif   

Of, pertaining to, or in accordance with a theory of evolution.

Adjective of → evolution.

evolutionary mass
  جرم ِ فرگشتی   
jerm-e fargašti (#)

Fr.: masse évolutive   

The stellar mass based on → effective temperature and → luminosity, as derived from → evolutionary tracks.

evolutionary; → mass.

evolutionary model
  مدل ِ فرگشت   
model-e fargašt (#)

Fr.: modèle d'évolution   

A model, based on theoretical calculations, which predicts the behavior of an astronomical entity (stars, galaxies, Universe) over time.

evolutionary; → model.

evolutionary stage
  گامه‌ی ِ فرگشت   
gâmeye fargašt

Fr.: étape d'évolution   

A particular step or phase in the evolution of an astronomical object.

evolutionary; → stage.

evolutionary time scale
  زمان-مرپل ِ فرگشت   
zamân-marpel-e fargašt

Fr.: échelle de temps d'évolution   

The characteristic time it takes an evolving astronomical object to pass from a step to another.

evolutionary; → time scale.

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