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

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory

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<< < -es -iv -ti 21 a p abe abs abs aca acc acc acr act ada adh Adr aer AGB air Alf Alg all alp alt AM amo ana And ang ani ano Ant Ant apa apo app app Ara Arc ari Arr ash ass ast ast asy atm ato att aut ave axi Bab bal Bal bar bar bea Bek Bes bia Big bin bin bip biv bla bli blu Boh Bol Bos bou bra bri bro buo cal cal can cap car Car cat cat CCD Cen cen CH cha cha che Che chr cir cir cit 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 con Cop Cor cor cor cos cos cou cou Cow cre cri cro cry cur cya Cyg dan dar dat de- deb dec dec ded def deg del dem den dep des det dev dia dif dif dih dio Dir dis dis dis dis dis dis DO don dou dow dro dur dwa dyn Dys ear ebb ecl edg egg Ein Ela ele ele ele ele ell eme emp enc eng ent epi equ equ equ esc eth Eur Eve exa exc exe exi exp exp ext ext ext fac fal far fed Fer fer fie fin fir fis fla flo flu fol for for fou fra fre Fre fro fut G-t gal gal gam gas Gau Gem gen geo geo geo gia Gli Gol gra gra gra gra gre gri gui H I Hag hal har hat He- hea hel Hel her Hes hie hig his hom hor hot Hub Hug hur hyd hyd hyg hyp ice ide ima Ima imp imp inc inc ind ine inf inf inf ing inn ins ins int int int int int int int int inv Io ion iro isl iso iso Jac jet jud jur Kel Kep kil Klo Kui Lag lam Lap Lar lat law lea len lep Lib lig lim lin lin Lio lit loc LOF lon Lor low lum lun Lup Lyo mac mag mag mag mag mag mai man Mar mas mas mat Max mea mec Meg Mer Mer met met Met mic Mid Mil min Mir mit mod mod mol mon Mor mou mul mul mys nan Nat nau nec neo neu nev New NGC no nom non non nor not nuc nuc num nut obj obs obs occ ocu oft ome Oor ope opp opt opt orb ord ori ort osc out ove oxi pai pan par par par par pas pea pen per per per per Per per pha phi pho pho pho phy pio Pla pla pla pla Pla plu Poi pol pol pol poo pos pos pot pra pre pre pre pre pri pri pro pro pro pro pro Pro pro pse pul pur qua qua qua qua que rac rad rad rad rad rad rad ran rar ray rea rea rec rec red red ref ref reg rel rel rel ren res res res res ret rev Ric rig rin roc roo rot rot Rus Sac sal sat sca sca Sch sci Scu sec sec Sed sel Sel sen ser Sex Sha she sho sid sig sil sim sin siz sla Sma sno sof sol sol sol sol sou sou spa spa spe spe spe sph spi spi spr 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 tek tem ter tes the the the the Tho thr tid tim Tis Too Tor tra tra Tra tra tra tri tri tru Tul tur two Typ ult un- und uni uni unk upp Urc utt val var vec vel ver vib vio vir vis voi vor wan wat wav wax wea Wei whi Wil win WN9 wor X-r yel you zer zod > >>

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velocity of light
  تندی ِ نور، تندای ِ ~   
tondi-ye nur, tondâ-ye ~

Fr.: vitesse de la lumière   

A → physical constant which represents the ultimate speed limit for anything moving through space, according to the theory of → special relativity. It is the speed of propagation of → electromagnetic waves in a vacuum, equal to 299,792.458 km/s (nearly 3 x 108 m/s). The velocity of light appears as the connecting link between mass and energy in the → mass-energy relation. Usually denoted by c, from L. celeritas "swiftness," from celer "swift," → acceleration.

velocity; → speed; → light.

velocity pressure
  فشار ِ توانیک   
fešâr-e tavânik

Fr.: pression dynamique   

dynamic pressure.

velocity; → pressure.

velocity profile
  فراپال ِ تندا   
farâpâl-e tondâ

Fr.: profil de vitesse   

A plot of the fluid velocity as a function of position.

velocity; → profile.

velocity space
  فضای ِ تندا، ~ تنداها   
fazâ-ye tondâyi, ~ tondâhâ

Fr.: espace de vitesses   

Of a dynamical system, a three-dimensional space which consists of the set of values that the velocity can take (vx, vy, vz). → phase space.

velocity; → space.

velocity-distance relation
  باز‌آنش ِ تندا-دورا   
bâzâneš-e tondâ-durâ

Fr.: relation vitesse-distance   

The linear relation wherein all galaxies are moving away from one another, with velocities that are greater with increasing distance of the galaxy. Same as → Hubble's law.

velocity; → distance; → relation.

vena contracta
  شاره‌گذر ِ ترنگیده   
šâre-gozar-e terengidé

Fr.: veine contractée   

The location in a → fluid stream where the → cross section of the → stream is at a minimum, and fluid velocity is the highest, such as in the case of a → jet issuing out of a → nozzle.

L. vena "channel;" contracta, "contracted," → contract.

Šâre-gozar "fluid passage," → fluid; → passage, terengidé, → contracted.

Venn diagram
  نمودار ِ وِن   
nemudâr-e Venn (#)

Fr.: diagramme de Venn   

A schematic diagram using circles to represent sets and the relationships between them. Each circle represents one set. Two or more may be overlapped. The areas of overlap indicate subsets.

Named after John Venn (1834-1923), a British logician and philosopher, who introduced the diagram; → diagram.

vent
  دودکش   
dudkaš (#)

Fr.: cheminée   

The subterranean conduit from the underlying → magma chamber through which a volcano ejects igneous material. Same as volcanic vent.

M.E. venten "to furnish (a vessel) with a vent," from O.Fr. esventer "to air," from es-, → ex-, + venter, from vent, from L. ventus "wind."

Dudkaš "chimney," literally "smoke extractor," from dud, → smoke, + kaš "to extract, to draw," present stem of kešidan/kašidan "to carry, draw, protract, trail, drag" (Mid.Pers. kešidan "to draw, pull;" Av. karš- "to draw; to plow," karša- "furrow;" cf. Skt. kars-, kársati "to pull, drag, plow;" Gk. pelo, pelomai "to move, to bustle;" PIE base kwels- "to plow").

Venturi tube
  لوله‌ی ِ ونتوری   
lule-ye Venturi

Fr.: débitmètre de Venturi, tube de ~   

A → device used to → measure the → quantity of → fluid  → flowing through a → pipe.

Named after Italian physicist Giovanni Battista Venturi (1746-1822); → tube

Venus
  ناهید   
Nâhid (#)

Fr.: Vénus   

The second → planet from the → Sun, at a mean distance of roughly 108.21 × 106 km (0.72 → astronomical units). The → greatest elongation of Venus is about 47°, making it visible at most about 3 hours after sunset or before sunrise. Venus has the most circular orbit of any planet in the solar system. Venus is only slightly smaller than Earth (95% of Earth's diameter, 80% of Earth's mass). Its chemical composition and density are comparable to those of the Earth. It takes Venus just under 224.401 days to orbit the Sun, compared to the 365 day → orbital period of the Earth. Venus' rotation is → retrograde, that is it actually rotates from east to west, as opposed to west to east (→ prograde) which is the common rotating direction of most other planets. Seen from Venus, the sun would rise in the west and set in the east. Moreover, it takes about 244 Earth days for Venus to rotate once (→ sidereal rotation). This is longer than its orbital period. The length of its → solar day is about 117 Earth days. → Venus rotation. Its axial tilt is only three degrees, so there are no seasons on Venus. The → atmosphere on the surface of Venus consists mostly of → carbon dioxide, with a small trace of → nitrogen. Venus has a surface pressure about 90 times that of the Earth. See also: → Venus visibility, → transit of Venus.

O.E., from L. Venus, the goddess of beauty and love in ancient Roman mythology, from venus "love, sexual desire, beauty, charm;" PIE base *wen- "to desire, love, wish;" cf. Av. vāunuš "lovingly," vantā- "beloved one, wife;" Skt. van- "to love, desire," vanánā- "desire," vanitā- "beloved one, wife;" O.H.G. wunsc(h) "wish," wunsken "to wish."

Nâhid, planet Venus, Mid.Pers. Anahid; O.Pers. anāhita- "immaculate, unstained," goddess of pure waters and fertility, from Av. arədvī-sūra-anāhita "valient and unsustained lord of waters," from arədvī- (Skt. Saravastī) probably "she who possesses water," + sūra- "strong, powerful" (Skt. śūra- "valiant, courageous") + anāhita- "unstained," from an- negation prefix + āhita "spotted."

Venus rotation
  چرخش ِ ناهید   
carxeš-e nâhid

Fr.: rotation de Vénus   

The → sidereal rotation period of Venus, or its → sidereal day, is 243.025 Earth days (retrograde). The length of a → solar day on Venus (that is one entire day-night period) is 116.75 Earth days, that is significantly shorter than the sidereal day because of the retrograde rotation. One Venusian year is about 1.92 Venusian solar days.

Venus; → rotation.

Venus visibility
  پدیداری ِ ناهید   
padidâri-ye Nâhid

Fr.: visibilité de Vénus   

The conditions under which Venus can be seen from Earth as it travels in its orbit around the Sun. The → synodic period of Venus, that is the time Venus takes to be seen again from the Earth in the same position with respect to the Sun, is 583,92 days or just over 19 months. When Venus is between Earth and Sun (→ inferior conjunction) or on the far side of the sun (→ superior conjunction), it is invisible in the Sun's glare. Since its → greatest elongation from the Sun is never more than 47°, Venus appears only as "the morning star" and "the evening star." So at its greatest → western elongation Venus will rise about three hours ahead of the Sun and at its greatest → eastern elongation it will set about three hours after sunset. Its entire cycle is as follows:
Day 0: Superior conjunction, "full Venus."
Day 35: Venus appears in evening sky.
Day 221: Greatest → eastern elongation, "last quarter."
Day 271: Retrogression of Venus begins.
Day 286: Disappearance from the evening sky.
Day 292: Inferior conjunction, "new Venus."
Day 298: Venus appears in morning sky.
Day 313: Retrogression ends.
Day 362: Greatest → western elongation, "first quarter."
Day 549: Disappearance from morning sky.
Day 584: Superior conjunction, "full venus."
Therefore, Venus is visible as an evening star for 286 Earth days, as a morning star for 251 days, and is invisible for 47 days.

In addition, the orbital periods of Earth and Venus are closely correlated. After 8 Earth years or 13 Venus orbits, the two planets assume almost the same relative positions -- just 0.032 percent away from a perfect orbital resonance of 8:13. After this period of about 2920 Earth days, Venus appears just 1.5° (about 22 hours) in advance of its former position. Moreover, Venus exhibit → phases because its orbit lies within the Earth's. When Venus situated on the far side of the Sun from Earth, the planet is fully illuminated from our point of view. But its disk is small, just 10'' across, because it is nearly 300 million km away. When Venus is almost closest to Earth, on the near side of the Sun, it's about 60 million km away. Then it appears as a slender but much brighter crescent with a disk nearly 50'' across. See also → transit of Venus.

Venus; → visibility.

verb
  کرواز   
karvâz

Fr.: verbe   

A member of a major category of words that refers to an action or a state. Verbs present a complex system of forms in Indo-European languages. The set of → inflectional forms of a verb is called a → conjugation. Verbs are usually distinguished for person and number along with tense and mood (if applicable).

M.E., from O.Fr. verbe from L. verbum "verb," originally "a word," from PIE root *wer- "to speak;" cf. Av. urvāta- "command;" Skt. vrata- "command, vow;" Gk. rhetor "public speaker," eirein "to speak, say;" Lith. vardas "name;" Goth. waurd, O.E. "word."

Karvâz, literally "action word," from kar- present stem of kardan "to do, make" (Mid.Pers. kardan; O.Pers./Av. kar- "to do, make, build," Av. kərənaoiti "he makes;" cf. Skt. kr- "to do, to make," krnoti "he makes, he does," karoti "he makes, he does," karma "act, deed;" PIE base kwer- "to do, to make") + vâz "word," variants vâž, âvâz, vâj, vât, vâ, → voice.

verbatim
  واژ-به-واژ   
vâž-be-vâž

Fr.: verbatim   

In exactly the same words; word for word.

From M.L. verbatim "word for word," from L. verbum "word," → verb.

Vâž-be-vâž, literally "word for word," from vâž, → word.

vergence
  گرایی   
gerâyi

Fr.: vergence   

Optics: A measure of the convergence or divergence of a pair of light rays, defined as the reciprocal of the distance between the point of focus and a reference plane.
Ophthalmology: The turning motion of the eyeballs toward or away from each other.

back formation from → convergence and → divergence, ultimately from L. vergere "to turn, bend, be inclined;" cognate with Pers. gardidan "to turn, to change," → version.

Gerâyi, from gerâyidan "to incline toward; to intend; to make for." Gerâ may be a variant of Mod.Pers. kil "bent, inclined" (k/g and l/r interchanges), from PIE base *klei- "to lean, incline," cognate with L. clinare "to bend" (E. declination, inclination, etc.), Gk. klinein "to cause to slope, slant, incline," Skt. sri- "to lean," O.Pers. θray-, Av. sray- "to lean," P.Gmc. *khlinen (Ger. lehnen, E. lean).

verifiability principle
  پروز ِ راست-جُست-پذیری   
parvaz-e râst-jost-paziri

Fr.: principe de vérifiabilité   

In logical positivism philosophy, the claim that a statement is literally meaningful (it expresses a proposition) if and only if it either actually has been verified or could at least in principle be verified.

Quality noun from → verifiable; → principle.

verifiable
  راست-جُست-پذیر   
râst-jost-pazir

Fr.: vérifiable   

That can be verified. → verify; → verification; → verifiability principle.

verify; → -able.

verification
  راست-جُست   
râst-jost

Fr.: vérification   

The act of verifying. The state of being verified.
The process of research and examination required to establish correctness, authenticity, or validity.

Verbal noun of → verify.

verify
  راست-جُستن، راست-جست کردن   
râst-jostan, râst-jost kardan

Fr.: vérifier   

To ascertain the truth or correctness of, as by examination, research, or comparison.

M.E. verifien, from M.Fr. verifier, from M.L. verificare "to make true," from L. verus "true;" → -fy.

Râst-jostan, literally "to seek the truth, to seek the right," from râst "right, true; just, upright, straight" (Mid.Pers. râst "true, straight, direct;" Soghdian rəšt "right;" O.Pers. rāsta- "straight, true," rās- "to be right, straight, true;" Av. rāz- "to direct, put in line, set," razan- "order;" cf. Skt. raj- "to direct, stretch," rjuyant- "walking straight;" Gk. orektos "stretched out;" L. regere "to lead straight, guide, rule," p.p. rectus "right, straight;" PIE base *reg- "move in a straight line," hence, "to direct, rule") + jostan/juyidan "to seek, strive for" (Proto-Iranian *iud- "to struggle for something, to fight;" Av. yūδ- "to fight, struggle;" Mod.Pers. justan, juy- "to search, seek, ask for;" cf. Mid.Pers. vijuyihitan "to search, seek").

vernal
  بهاری   
bahâri (#)

Fr.: vernal   

Of or pertaining to spring. → vernal equinox.

From L. vernalis "of the spring," from vernus "of spring," from uēr "spring," cognate with Pers. bahâr, as below.

Bahâri of or pertaining to bahâr "spring;" Mid.Pers. wahâr "spring;" O.Pers. vāhara- "spring time," θūra-vāhara- "name of a spring month;" Av. vaηhar "spring;" cf. Skt. vasara- "relating or appearing in the morning;" Gk. ear "spring;" L. uēr "spring," vernus "of spring;" O.N. vār "spring;" Lith. vasara "summer;" O.C.S. vesna "spring."

<< < -es -iv -ti 21 a p abe abs abs aca acc acc acr act ada adh Adr aer AGB air Alf Alg all alp alt AM amo ana And ang ani ano Ant Ant apa apo app app Ara Arc ari Arr ash ass ast ast asy atm ato att aut ave axi Bab bal Bal bar bar bea Bek Bes bia Big bin bin bip biv bla bli blu Boh Bol Bos bou bra bri bro buo cal cal can cap car Car cat cat CCD Cen cen CH cha cha che Che chr cir cir cit 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 con Cop Cor cor cor cos cos cou cou Cow cre cri cro cry cur cya Cyg dan dar dat de- deb dec dec ded def deg del dem den dep des det dev dia dif dif dih dio Dir dis dis dis dis dis dis DO don dou dow dro dur dwa dyn Dys ear ebb ecl edg egg Ein Ela ele ele ele ele ell eme emp enc eng ent epi equ equ equ esc eth Eur Eve exa exc exe exi exp exp ext ext ext fac fal far fed Fer fer fie fin fir fis fla flo flu fol for for fou fra fre Fre fro fut G-t gal gal gam gas Gau Gem gen geo geo geo gia Gli Gol gra gra gra gra gre gri gui H I Hag hal har hat He- hea hel Hel her Hes hie hig his hom hor hot Hub Hug hur hyd hyd hyg hyp ice ide ima Ima imp imp inc inc ind ine inf inf inf ing inn ins ins int int int int int int int int inv Io ion iro isl iso iso Jac jet jud jur Kel Kep kil Klo Kui Lag lam Lap Lar lat law lea len lep Lib lig lim lin lin Lio lit loc LOF lon Lor low lum lun Lup Lyo mac mag mag mag mag mag mai man Mar mas mas mat Max mea mec Meg Mer Mer met met Met mic Mid Mil min Mir mit mod mod mol mon Mor mou mul mul mys nan Nat nau nec neo neu nev New NGC no nom non non nor not nuc nuc num nut obj obs obs occ ocu oft ome Oor ope opp opt opt orb ord ori ort osc out ove oxi pai pan par par par par pas pea pen per per per per Per per pha phi pho pho pho phy pio Pla pla pla pla Pla plu Poi pol pol pol poo pos pos pot pra pre pre pre pre pri pri pro pro pro pro pro Pro pro pse pul pur qua qua qua qua que rac rad rad rad rad rad rad ran rar ray rea rea rec rec red red ref ref reg rel rel rel ren res res res res ret rev Ric rig rin roc roo rot rot Rus Sac sal sat sca sca Sch sci Scu sec sec Sed sel Sel sen ser Sex Sha she sho sid sig sil sim sin siz sla Sma sno sof sol sol sol sol sou sou spa spa spe spe spe sph spi spi spr 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 tek tem ter tes the the the the Tho thr tid tim Tis Too Tor tra tra Tra tra tra tri tri tru Tul tur two Typ ult un- und uni uni unk upp Urc utt val var vec vel ver vib vio vir vis voi vor wan wat wav wax wea Wei whi Wil win WN9 wor X-r yel you zer zod > >>