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: 212
vocal cord
  تار ِ آواز   
târ-e âvâz

Fr.: corde vocale   

The sharp edge of a fold of mucous membrane stretching along either wall of the larynx from the angle between the laminae of the thyroid cartilage to the vocal process of the arytenoid cartilage. Vibrations of these cords are used in voice production (The American Heritage).

voice; → cord.

Vogt-Russell theorem
  فربین ِ فوکت-راسل   
farbin-e Vogt-Russell

Fr.: théorème de Russell-Vogt   

The internal structure and all observable characteristics of a star (such as luminosity and temperature) are determined uniquely by its mass, chemical composition, and age. Same as → Russell-Vogt theorem.

Named after the German astronomer Heinrich Vogt (1890-1968) and the American astronomer Henry Norris Russell (1877-1957); → theorem.

voice
  آواز   
âvâz (#)

Fr.: voix   

Sounds made when speaking or singing.

M.E., from O.Fr. voiz, from L. vox "voice, sound, utterance, cry, call, speech, sentence, word," related to vocare "to call;" akin to Pers. âvâz "voice," as below.

Âvaz "voice, sound, song," related to âvâ "voice, sound, song" (both prefixed forms), bâng "voice, sound, clamour" (Mid.Pers. vâng), vâžé "word," variants vâj-, vâk-, vâ-, vâz-, vât-; Av. vacah- "word," vaocanghê "to decalre" (by means of speech), from vac- "to speak, say;" cf. Skt. vakti "speaks, says," vacas- "word;" Gk. epos "word;" L. vox "voice;" PIE base *wek- "to speak."

void
  تهی   
tohi (#)

Fr.: vide   

1) An empty space; a gap or opening; emptiness. → vacuum.
2) A large region of cosmic space without galaxies. The first of these voids to be discovered lies in the direction of → Bootes and is some 300 million → light-years across. It is estimated that voids take up about 98% of the volume of the Universe, with clusters of galaxies concentrated in the thin walls that surround them.

M.E. voide, from O.Fr. voide "empty, vast, wide, hollow," from L. vocivus "unoccupied, vacant," related to vacuus "empty," → vacuum.

Tohi "empty" (variants in dialects Tabari tisâ, Saraxsi, Lâsgardi, Sangesari tusâ, Aftari tussâ); Mid.Pers. tuhig; Av. taoš- "to become empty," pres. tusa-, caus. taošaya-, tusən "they lose their posture;" cf. Skt. tuccha-, tucchya- "empty;" L. tesqua, tesca "deserted place;" Rus. tošcij "hollow;" PIE base *teus- "to empty."

Voigt effect
  اسکر ِ فوکت   
oskar-e Voigt

Fr.: effet Vogt   

Double refraction occurring when a strong → magnetic field is applied to a vapor through which light is passing perpendicular to the field.

Named after Woldemar Voigt (1850-1919), a German physicist (1908, Magneto- und Elektro-optik, B. G. Teubner, Leipzig); → effect.

Voigt profile
  فراپال ِ فوکت   
farâpâl-e Voigt

Fr.: profil de Voigt   

A spectral profile in which a → spectral line is broadened by two types of mechanisms, one of which alone would produce a & rarr; Gaussian profile (usually, as a result of the → Doppler broadening), and the other would produce a → Lorentzian profile.

After Woldemar Voigt (1850-1919), a German physicist; → profile.

Volans
  ماهی ِ پرنده   
Mâhi-ye Parandé (#)

Fr.: Poisson volant   

The Flying Fish. A constellation in the southern hemisphere at 7h 40m right ascension, -70° declination. Originally called Piscis Volans, and invented by Johann Bayer (Uranometria, published in 1603). Abbreviation: Vol; Genitive: Volantis.

L. Volans "flying," from volare "to fly."

Mâhi-ye Parandé, from mâhi "fish" (Mid.Pers. mâhik; Av. masya-; cf. Skt. matsya-; Pali maccha-) + parandé "flying, flier," from paridan "to fly" (Mid./Mod.Pers. par(r) "feather, wing," Av. parəna- "feather, wing;" cp. Skt. parna "feather," E. fern; PIE *porno- "feather").

volatile
  پرا   
parrâ

Fr.: volatile   

A substance that vaporizes at relatively low temperatures (e.g. H2O, CO2, CO, CH4, NH3, and so forth). The opposite of volatile is → refractory.

M.E., from M.Fr. volatile, from L. volatilis "fleeting, transitory, flying," from p.p. stem of volare "to fly," of unknown origin.

Parrâ "flying," from paridan "to fly in the air," → Volans.

volatile element
  بن‌پار ِ پرا   
bonpâr-e parrâ

Fr.: élément volatile   

In → planetary science, any of a group of → chemical elements and → chemical compounds with relatively low → boiling points that are associated with a planet's or moon's → crust and/or → atmosphere. For example, H, He, C, N, O are underabundant (relative to the solar → photospheric values) in all types of → meteorites, including the C1 → carbonaceous chondrites. Any heating of the meteorite parent body subsequent to its formation would tend to drive the volatile elements out of the rock, whence it sublimated into → interplanetary medium.

volatile; → element.

volcanic
  آتشفشانی   
âtašfešâni (#)

Fr.: volcanique   

Of or relating to a volcano. Characterized by volcanoes.

volcano; → -ic.

volcanic eruption
  اسدرش ِ آتشفشانی   
osdareš-e âtašfešâni

Fr.: éruption volcanique   

The explosive ejection of superheated matter from a → volcano.

volcanic; → eruption.

volcanic explosivity index (VEI)
  دیشن ِ اسکفتندگی ِ آتشفشانی   
dišan-e oskaftandegi-ye âtašfešâni

Fr.: indice d'explosivité volcanique   

A logarithmic scale, ranging from 1 to 8, used to measure the intensity of volcano eruptions. The VEI is based on several factors: the degree of fragmentation of the volcanic products released by the eruption, the amounts of sulfur-rich gases that form stratospheric aerosols, the volume of the eruptions, their duration, and the height is reached. The largest eruptions (8) produce an amount of bulk volume of ejected → tephra of ~ 1,000 km3.

volcanic; → explosivity; → index.

volcanic vent
  دودکش ِ آتشفشانی   
dudkaš-e âtašfešâni (#)

Fr.: cheminée volcanique   

vent.

volcanic; → vent.

volcano
  آتشفشان   
âtašfešân (#)

Fr.: volcan   

An opening in the Earth's → crust from which → lava, → ash, and hot → gases flow or are → ejected during an → eruption.

From It. vulcano, from L. Vulcanus, → Vulcan.

Âtašfešân, literally "fire disperser, dispersing fire," from âtaš, → fire, + fešân contraction of afšân, from afšândan "to spread, scatter," Mid.Pers. afšân "to spread, to scatter;" ultimately from Proto-Ir. *apašan-, from root *šan- "to shake" (Cheung 2007).

volt
  ولت   
volt (#)

Fr.: volt   

The SI unit of potential difference, defined as the difference of potentials across the ends of a conductor in which a power 1 watt is liberated when a current of 1 ampere flows through it.

In honor of the Italian scientist Alessandro Volta (1745-1827), known for his pioneering work in electricity and the invention of the first battery.

voltage
  ولتاژ   
voltâž (#)

Fr.: voltage, tension   

The electric potential difference expressed in volts.

From → volt.

voltaic
  ولتایی   
voltâyi (#)

Fr.: voltaïque   

Of, relating to electricity or electric currents, especially when produced by chemical action, as in a cell. → photovoltaic detector.

Alessandro Volta (1745-1827), Italian physicist, known for his pioneering work in electricity.

volume
  گنج   
gonj (#)

Fr.: volume   

The amount of space occupied by a three-dimensional object or region of space, expressed in cubic units.

M.E. volum(e), from O.Fr. volume, from L. volumen (genitive voluminis) "roll (as of a manuscript), coil, wreath," from volvere "to turn around, roll."

Gonj "volume," gonjidan "to be contained or held; to hold;" gonjâyeš "capacity, holding, containing;" Mid.Pers. winj- "to be contained;" Proto-Iranian *uiac-/*uic-; cf. Skt. vyac- "to contain, encompass," vyás- "extent, content, extension;" L. uincire "to bind."

volume-limited survey
  بردید با گنج ِ حدمند   
bardid bâ gonj-e hyaddmand

Fr.: relevé limité en volume   

A survey in which the observed objects are contained in a given volume of space.

volume; → limited; → survey.

von Zeipel paradox
  پارادخش ِ فون زایپل   
pârâdxš-e von Zeipel

Fr.: paradoxe de von Zeipel   

A → rotating star cannot simultaneously achieve → hydrostatic equilibrium and → rigid body rotation. The paradox can be solved if → baroclinic flows (essentially a → differential rotation and a → meridional circulation) are included. For a broader view of the subject see: M. Rieutord, 2006, in Stellar Fluid Dynamics and Numerical Simulations: From the Sun to Neutron Stars, ed. M. Rieutord & B. Dubrulle, EAS Publ., 21, 275, arXiv:astro-ph/0608431.

von Zeipel theorem; → paradox.

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