An Etymological Dictionary of Astronomy and Astrophysics
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فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

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<< < -es -iv -ti 21- A r abe abs abs acc acc acc act act ada adi adu aff age alc Alf ali all alp alt ama amp ana ang ang ann ano ant ant ape apo app aps arc Arg ari art ass ast ast ast atm ato att aur aut axi B r bac Bal Bar Bar Bay bec Ber Bet Bie bij bin bio bis bla bla blu blu bol Bor bou Bra bre bro Bug C-s cal Cam can car Car Cas cat cav cel cen cer Cha cha cha che cho cir cir cir 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 coo cor cor cor cos cos cos Cou cou Cra Cre cri cro cub cur cyc cyl dar dat daw de- Deb dec dec dee def deg del Den dep der det deu dew dic dif dif dil dip dir dis dis dis dis dis diu dog Dop dou Dra dua dus dwa dyn e-f Ear ecl eco edu eig Ein ela ele ele ele Ele elo emi emp ene Enl env epi equ equ Eri est Euc eva evo exc exc exh Exo exp exp ext ext f(R fac fam fat fee Fer Fib fig fin fir fix fle flu foc for for for fra fre Fre fri fun fuz Gal gal gal Gam gau Gay gen Geo geo geo geo gim glo gov gra gra gra gra gre gro Gun hab hal han Har haz hea hel hel Hen Her het Hig hil hol Hoo hor hou Hub hum hyd hyd hyd hyp hys ide ign ima imp imp inc inc ind Ind inf inf inf inf inn ins ins int int int int int int int int inv ion ion Irr iso iso iso jan jit Jul jus Kel ker kin kni La lam lan Lap las lat Lay Led Len let lif lig lin lin lin liq Lit loc log lon lou low lum lun Lym M d Mag mag mag mag mag mag maj man mar mas mas mat mea mea mec mem mer Mes met met mho mic Mie Mil min mis MKS MOd mol Mon moo mot mul mul myo nak Nas nat neb neg neu neu New New nit noi non non nor nor nuc nuc nul nut obj obl obs occ oct off oli oni ope opp opt opt orb ord org orp osc out ove oxi pai Pan par par Par par pas Pav Pel per per per per Per per pha phi pho pho pho phy Pip Pla pla PLA pla ple plu pol pol pol pol pop pos pos pot Pra pre pre pre Pri pri pri pro pro pro pro pro pro pro Pto pul pur qua qua qua qua qui rad rad rad rad rad rad rai ran rar Ray rea rea rec rec red red ref ref reg rel rel rel rep res res res res ret RHB rid rig ris roc Ros rot rub Rut Sag sam sat sca sca Sch sci Sea sec sec see sel sem sen set Sha sha shi shu sid sil sim sin SIS ski Slo smo Soc sol sol sol sol son sou spa spa spe spe spe sph spi spi Spo 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 tel tem ter tes the the the the Tho thr tid tim Tit top tot tra tra TRA tra tre tri tri tru Tun Tus tym Typ ult unb und uni uni uns upp Urs vac van var Vei Ven ver vic Vir vir vis vol W 4 war wat wav wea wed wet wid win WN2 Wol wri xen yok zen zin > >>

Number of Results: 12955 Search : far
equilibrium state
  استات ِ ترازمندی، حالت ِ ~   
estât-e tarâzmandi, hâlat-e ~

Fr.: état d'équilibre   

A state in which a → thermodynamic system is in → thermodynamic equilibrium.

equilibrium; → state.

equinoctial
  هموگانی   
hamugâni

Fr.: équinoxial   

Of or relating to an equinox or to the equality of day and night.

Adjective of → equinox.

equinoctial colure
  کلدم ِ هموگانی   
koldom-e hamugâni

Fr.: colure d'équinoxe   

The great circle of the celestial sphere through the celestial poles and equinoxes; the hour circle of the vernal equinox. → colure.

equinoctial; → colure.

equinoctial points
  نقطه‌ها‌ی ِ هموگانی   
noqtehâ-ye hamugâni

Fr.: points équinoxiaux   

One of the two points of intersection of the ecliptic and the celestial equator. Same as equinox.

equinoctial; → point.

equinox
  هموگان   
hamugân

Fr.: équinoxe   

1) One of the two points on the → celestial sphere where the → celestial equator intersects the → ecliptic, that is when the apparent → ecliptic longitude of the Sun is 0° or 180°.
2) Either of the times at which the center of the Sun's disk passes through these points. → autumnal equinox; → vernal equinox.
At equinox, the length of the day and the night are equal all over the globe. The equinox is not a fixed point; it moves due to → precession and → nutation. If only precession is considered, we deal with the → mean equinox of date. If nutation is also taken into account, then we are concerned with the → true equinox.

M.E., from O.Fr. équinoxe, from M.L. equinoxium "equality of night (and day)," from L. æquinoctium, from æquus, "→ equal" + nox "→ night" (gen. noctis). In Gk. isimeria "equal day," from isos "equal," → iso-, + hemera "day."

From hamug, → equal, + -ân suffix denoting time and place.

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.

equipotential surface
  رویه‌ی ِ هموگ-توند   
ruye-ye hamugtavand

Fr.: surface équipotentielle   

An imaginary surface surrounding a body, or group of bodies, over which the gravitational field is of constant strength and, at all points, is directed perpendicular to the surface. For a single star the surface is spherical. In a close binary system the equipotential surface of the components interact to become hourglass-shaped. → Roche lobe; → Lagrangian points.

From → equi-; → potential; → surface.

equivalence
  هموگ‌ارزی   
hamug-arzi (#)

Fr.: équivalence   

The state or fact of being equivalent; equality in value, force, significance, etc. → covalence.

From M.F. from M.L. æquivalentia, from L. æquivalent-, → equivalent.

Hamug-arzi, noun of hamug-arz, → equivalent.

equivalence principle
  پروز ِ هموگ‌ارزی   
parvaz-e hamug-arzi

Fr.: principe d'équivalence   

A fundamental concept of physics, put forward by A. Einstein, that states that gravitational and inertial forces are of a similar nature and indistinguishable. In other words, acceleration due to gravity is equivalent to acceleration due to other forces, and gravitational mass is the same as inertial mass. Same as the → principle of equivalence.

equivalence; → principle.

equivalent
  هموگ‌ارز   
hamug-arz

Fr.: équivalent   

Equal in value, measure, force, effect, significance, etc.

From L.L. æquivalentem (nominative æquivalens) "equivalent," p.p. of æquivalere "be equivalent," from L. æquus, → equal + valere "to be worth; be strong."

Hamug-arz, from hamug-, → equi-, + arz 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."

equivalent depth
  ژرفای ِ هم-ارز   
žarfâ-ye ham-arz

Fr.: profondeur équivalente   

A measure of the number of particles passing a given point in a → planetary ring per unit time. It is obtained by multiplying the physical width of the ring by its average → optical depth. For the variable-width eccentric rings of → Uranus, equivalent depth remains almost constant around a given ring (Ellis et al., 2007, Planetary Ring Systems, Springer).

equivalent; → depth.

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.

equivalent width
  پهنای ِ هموگ‌ارز   
pahnâ-ye hamug-arz

Fr.: largeur équivalente   

1) A measure of the → strength of a → spectral line. The equivalent width is the width of a → rectangle centered on a spectral line that, on a plot of → intensity against → wavelength, has the same → area as the line.
2) The width-integrated → optical depth of a → planetary ring. For rings with very small optical depths, the equivalent width is very nearly equal to the equivalent depth (Ellis et al., 2007, Planetary Ring Systems, Springer).

equivalent; → width.

Equuleus
  پاره اسب، کره اسب   
Pâré asb (#), Korré Asb

Fr.: Petit Cheval   

The Foal. A small, faint constellation in the northern hemisphere, lying between → Delphinus and → Pegasus, at 21h 10m right ascension, 5° north declination. Its brightest star, Kitalpha, has a visual magnitude of 3.9. Abbreviation: Equ; Genitive: Equulei.

L. Equuleus "little horse," diminutive of equus "horse," from PIE base *ekwos "horse" (cf. Pers. asb; Av. aspa- "horse;" Skt. áśva-; Gk. hippos; O.E. eoh; Arm. ēš). The origin of Equuleus is not clear. It is not mentioned in any classical Gk. or Roman myths. The first mention of the constellation was in Ptolemy's catalog, where it is referred to as Hippou Protome "the bust or upper part of an animal figure." Some mythologists have associated Equuleus with the foal Celeris, the brother of the winged horse Pegasus, given to Castor by Mercury.

Pâré asb "part of a horse," from pâré "piece, part, portion, fragment" (Mid.Pers. pârag "piece, part, portion; gift, offering, bribe;" Av. pāra- "debt," from par- "to remunerate, equalize; to condemn;" PIE *per- "to sell, hand over, distribute; to assign;" cf. L. pars "part, piece, side, share," portio "share, portion;" Gk. peprotai "it has been granted;" Skt. purti- "reward;" Hitt. pars-, parsiya- "to break, crumble") + asb "horse," Mid.Pers. asb; O.Pers. asa- "horse;" Av. aspa- "horse," aspā- "mare," āsu.aspa- "unbound horse;" Skt. áśvā- "mare;" cognate with L. equus, as above.
Korré asb, from korré "foal, colt of asb," as above. Mod.Pers. korré "baby of an animal, colt;" Laki korr "son, boy," kol "little mare (1-2 years old);" Lori kor "son, boy;" Kurd kur "son, boy;" Malâyeri kora "boy," korra "colt;" cf. Gk. kouros, koros "boy, child;" Skt. kúla- "race, household; herd, flock, multitude," svakúla- "one's own family or race;" Sogd. kur "child." Interestingly, the "group, herd" sense is present also in Pers. dialects Tâleši kavla "group, multitude;" Gilaki kowge "group, tribe."

era
  دوران   
dowrân (#)

Fr.: ère   

1) General: A period of time marked by a distinctive character, events, etc.
2) A system of chronological notation reckoned from a given date.
3) Geology: A subdivision of geologic time that is longer than a period but shorter than an eon. Precambrian, Paleozoic, Mesozoic, and Cenozoic are the eras of the time scale from oldest to youngest.

From L.L. æra, era "fixed date, era, epoch from which time is reckoned," probably identical with L. æra "counters used for calculation," plural of aes "brass, money," from PIE *aus- "gold" (cf. Av. aiiah- "metal," aiianhaēna- "made of metal;" Skt. áyas- "metal;" O.H.G. ēr "ore;" O.E. ora "ore, unworked metal;" Ger. ehern "brazen").

Dowrân, from Ar. daur "age, time; revolution."

Eratosthenes' method
  روش ِ اراتوستنس   
raveš-e Eratosthenes

Fr.: méthode d'Eratosthène   

A simple way of calculating the Earth's → circumference using two sticks and two theorems of the → Euclidean geometry. Eratosthenes calculated the length of a → meridian arc by measuring the shadow cast by a vertical → gnomon at noon on the → summer solstice. In Cyene (→ tropic of Cancer), no shadow is cast whereas in Alexandria, further north, the shadow is cast at an angle of 1/50 of 360° (measured using a → scaphe), or 7.2°, from the vertical. The circumference is therefore equal to 50 times the distance between the two cities. The distance from Syene to Alexandria was 5,000 stadia, which when multiplied by 50 gives the measure for the Earth's circumference, 250,000 stadia. Estimating the accuracy of this result is not easy because the unit of stadium is not uniquely defined in the ancient world. The most likely reconstruction puts Eratosthenes' stadium in the range 155-185m, implying an error of about 3% below or 15% above the true value. The modern value for the equatorial circumference of the Earth is 40,075 km. As scholars have pointed out, Eratosthenes' experiment was marred by several errors: Syene is not on the Tropic of cancer, it is not on the same meridian as Alexandria, and the distance between the two cities is less than he estimated. But the errors tended to cancel each other out, so his estimate was relatively accurate. See also: → Mamun's method, → Biruni's method.

Eratosthenes (c. 276-194 B.C.), Gk. mathematician, astronomer, and geographer. He studied in Athens and later became a librarian in Alexandria. His treatise On the Measuring of the Earth is lost. The account of his experiment has been preserved in Cleomedes (probably first century A.D.). See also → sieve of Eratosthenes; → experiment.

erg
  ارگ   
erg (#)

Fr.: erg   

The → CGS unit of → energy; the → work done by a → force of 1 → dyne acting over a distance of 1 → centimeter. 1 erg = 10-7 → joules = 6.242 × 1011 → electron-volts.

From Gk. ergon "work," from PIE base *werg- "to work" (cf. Av. varəz- "to work, do, perform, exercise;" Mod.Pers. varz-, varzidan "to labor, exercise, practise;" Arm. gorc "work;" Lith. verziu "tie, fasten, squeeze," vargas "need, distress;" Goth. waurkjan; O.E. wyrcan "work," wrecan "to drive, hunt, pursue").

ergodic
  ارگودیک   
ergodik (#)

Fr.: ergodique   

The property of a dynamical system such that in an interval of sufficient duration, it will return to states that are closely similar to previous ones.

From → erg + Gk. (h)od(os) "way, road" + → ic.

ergonomics
  ورزداتیک   
varzdâtik

Fr.: ergonomie   

The study of the relationship between people and their working environment, in particular its effect on a person's efficiency. Ergonomics is applied in designing equipment and office systems to maximize productivity by reducing discomfort and fatigue of people in their workplace.

From Gk. ergon "work," → erg, + -nomics, → -nomy, → -ics.

Varzdâtik, from varz "work, " cognate with Gk. ergon, → erg, + dâtik "law, rule," → -nomy.

ergosphere
  ارگ‌سپهر   
ergsepehr

Fr.: ergosphère   

The region between the → event horizon and the → stationary limit of a rotating → Kerr black hole. It is possible for a particle falling inside the ergosphere to break into two parts, one of which will fall into the black hole and the other will come out.

erg + → sphere.

<< < -es -iv -ti 21- A r abe abs abs acc acc acc act act ada adi adu aff age alc Alf ali all alp alt ama amp ana ang ang ann ano ant ant ape apo app aps arc Arg ari art ass ast ast ast atm ato att aur aut axi B r bac Bal Bar Bar Bay bec Ber Bet Bie bij bin bio bis bla bla blu blu bol Bor bou Bra bre bro Bug C-s cal Cam can car Car Cas cat cav cel cen cer Cha cha cha che cho cir cir cir 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 coo cor cor cor cos cos cos Cou cou Cra Cre cri cro cub cur cyc cyl dar dat daw de- Deb dec dec dee def deg del Den dep der det deu dew dic dif dif dil dip dir dis dis dis dis dis diu dog Dop dou Dra dua dus dwa dyn e-f Ear ecl eco edu eig Ein ela ele ele ele Ele elo emi emp ene Enl env epi equ equ Eri est Euc eva evo exc exc exh Exo exp exp ext ext f(R fac fam fat fee Fer Fib fig fin fir fix fle flu foc for for for fra fre Fre fri fun fuz Gal gal gal Gam gau Gay gen Geo geo geo geo gim glo gov gra gra gra gra gre gro Gun hab hal han Har haz hea hel hel Hen Her het Hig hil hol Hoo hor hou Hub hum hyd hyd hyd hyp hys ide ign ima imp imp inc inc ind Ind inf inf inf inf inn ins ins int int int int int int int int inv ion ion Irr iso iso iso jan jit Jul jus Kel ker kin kni La lam lan Lap las lat Lay Led Len let lif lig lin lin lin liq Lit loc log lon lou low lum lun Lym M d Mag mag mag mag mag mag maj man mar mas mas mat mea mea mec mem mer Mes met met mho mic Mie Mil min mis MKS MOd mol Mon moo mot mul mul myo nak Nas nat neb neg neu neu New New nit noi non non nor nor nuc nuc nul nut obj obl obs occ oct off oli oni ope opp opt opt orb ord org orp osc out ove oxi pai Pan par par Par par pas Pav Pel per per per per Per per pha phi pho pho pho phy Pip Pla pla PLA pla ple plu pol pol pol pol pop pos pos pot Pra pre pre pre Pri pri pri pro pro pro pro pro pro pro Pto pul pur qua qua qua qua qui rad rad rad rad rad rad rai ran rar Ray rea rea rec rec red red ref ref reg rel rel rel rep res res res res ret RHB rid rig ris roc Ros rot rub Rut Sag sam sat sca sca Sch sci Sea sec sec see sel sem sen set Sha sha shi shu sid sil sim sin SIS ski Slo smo Soc sol sol sol sol son sou spa spa spe spe spe sph spi spi Spo 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 tel tem ter tes the the the the Tho thr tid tim Tit top tot tra tra TRA tra tre tri tri tru Tun Tus tym Typ ult unb und uni uni uns upp Urs vac van var Vei Ven ver vic Vir vir vis vol W 4 war wat wav wea wed wet wid win WN2 Wol wri xen yok zen zin > >>