An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



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Number of Results: 442
  لکه‌ی ِ زرد   
lake-ye zard (#)

Fr.: fovéa   

A small depression, approximately 1.5 millimeters in diameter, at the back of the → retina. It forms the area of the most acute vision.

Contraction of fovea centralis, from L. fovea "small pit," of unknown origin.

Lake-ye zard, literally "yellow spot," from laké, → spot, zard, → yellow.

barxâl (#)

Fr.: fractal   

A geometrical or physical structure that repeats itself or nearly repeats itself on many different scales of magnification.

From Fr. fractale, term coined by Benoit Mandelbrot (1975), from frac(tus) "broken, uneven", → fraction, + -ale-al.

Barxâl, from barx, → fraction, + -âl-al.

fractal cosmology
  کیهانشناخت ِ برخالی   
keyhânšenâxt-e barxâli

Fr.: cosmologie fractale   

The postulate that the concentrations of matter in the Universe follow a → fractal structure over a wide range of scales.

fractal; → cosmology.

fractal structure
  ساختار ِ برخالی   
sâxtâr-e barxâli

Fr.: structure fractale   

A → hierarchial structure that can be likened to fractals.

fractal; → structure

barxé (#)

Fr.: fraction   

A rational number of the form a/b where a is called the numerator and b is called the denominator.

From L.L. fractionem (nom. fractio) "a breaking in pieces," from frangere "to break," from PIE base *bhreg- "to break" (cf. Goth. brikan, O.E. brecan "to break;" Lith. brasketi "crash, crack").

Barxé, from barx "lot, portion," variant bahr, from Mid.Pers. bahr "lot, share, portion," Av. baxəδra- "portion."


Fr.: fractionnaire, fractionné, partiel   

1) Math.: Pertaining to fractions; constituting a fraction.
2) Chemistry: Of or relating to any process by which parts of a mixture are separated by exploiting differences in their physical properties, such as their boiling points, solubility, or other characteristics.

fraction; → -al.

fractional sky coverage
  پوشش ِ برخه‌ای ِ آسمان   
pušeš-e barxe-yi-ye âsmân

Fr.: couverture partielle du ciel   

The portion of the 4π → steradians of the sky that a radiotelescope can observe from a given location on Earth over a 24-hour time interval.

fractional; → sky; → coverage.


Fr.: fractionner   

1) To break something up into smaller parts.
2) To separate a mixture into ingredients or portions having different properties, as by distillation or otherwise.

From → fraction + -ate a suffix forming verbs or nouns, from L. -atus, -ata, -atum.

Barxândan, from barx, barxé, → fraction, + -ândan suffix of transitive verbs.


Fr.: fractionnement   

1) Any of various methods of separating the components of a mixture into fractions of different properties.
2) → isotope fractionation

Verbal noun from → fractionate.

  ۱) لته، لت، پاره؛ ۲) لتپار شدن؛ ۳) لتپاریدن   
1) latté (#), latt (#), pâré (#); 2) latpâr šodan (#); 3) latpâridan

Fr.: 1) fragment; 2) se fragmenter; 3) fragmenter   

1) (n.) A part broken off or detached.
2) (v.intr.) To collapse or break into pieces.
3) ( To break something into pieces.

From L. fragmentum, from frangere "to break."

1) Latté, lat, variant laxt, laxté "piece, part;" 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 assigne;" 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."
2) and 3) Verbal forms.


Fr.: fragmentation   

Generally, the process of breaking up into smaller parts. In particular, the splitting of a large molecular cloud into smaller, denser clumps. → cloud fragmentation.

From → fragmenta + -ation, a combination of -ate and -ion, used to form nouns from stems in -ate.

Latpâreš, verbal noun from latpâridan, → fragment.

fragmentation process
  فراروند ِ لتپارش   
farâravand-e latpâreš

Fr.: processus de fragmentation   

The succession of physical events that results in the breaking of a → molecular cloud into several → fragments.

fragmentation; → process.

  ۱) چارچوب؛ ۲)، ۳) تصویرک   
1) cârcub (#); 2), 3) tasvirak

Fr.: 1) cadre; 2), 3) image   

1) A border or case for enclosing a picture, mirror, etc.; a structure for admitting or enclosing something.
2) One of the successive pictures on a roll of movie film or videotape.
3) In computers, the information or image on a screen or monitor at any one time.

Frame, from M.E. verb framen "to prepare (timber)," from O.E. framian "to avail, profit."; cf. O.H.G. (gi)framon "to do."

1) Cârcub "frame," from câr, contraction of cahâr "four" (→ four) + cub "stick, satff, beam," Mid.Pers. côp "wood, stick." 2) Tasvirak from Ar. tasvir "image" + -ak suffix of relation and similarity (as in poštak, dastak, nâxonak), → fibril.

frame dragging
  کرّه‌ی ِ چارچوب، چارچوب-کرّه   
kerre-ye cârcub, cârcub-kerré

Fr.: entraînement des repères, effet Lense-Thirring   

The alteration in the → free fall motion of a test → mass in the presence of a massive → rotating object, as compared to the identical case of a non-rotating object. This dragging of → inertial frames is predicted by → general relativity. Also called → Lense-Thirring effect.

frame; → drag.

frame frequency
  بسامد ِ تصویر   
basâmad-e tasvir

Fr.: fréquence image   

The number of times per second that the frame is scanned in television. Also known as picture frequency.

frame; → frequency.

frame of reference
  چارچوب ِ بازبرد   
câcub-e bâzbord

Fr.: système de référence   

A set of axes to which positions and motions in a system can be referred.

frame; → reference.


Fr.: cadrage   

The process of adjusting a television picture to a desired position in the direction of progression.

From → frame + → -ing.

Cârcubeš, verbal noun of cârcubidan, from cârcubframe.

frânsiom (#)

Fr.: francium   

An extremely rare radioactive chemical element; symbol Fr. Atomic number 87; atomic weight of most stable isotope 223; melting point about 27°C; boiling point about 677°C. Its most stable isotope (half-life about 22 minutes) occurs naturally, to a very limited extent, in uranium minerals. More than 30 other isotopes of francium are known; some are prepared by bombarding thorium with protons, deuterons, or alpha particles.

From France, where the French physicist Marguerite Perey (1919-1975) discovered it in 1939 in the alpha particle decay of actinium.

Fraunhofer line
  خط ِ فراؤنهوفر   
xatt-e Fraunhofer

Fr.: raie de Fraunhofer   

One of many absorption lines and bands in the spectrum of the Sun. The most prominent features are labeled with capital letters A to K, starting at the red end. The A and B bands are now known to be caused by absorption in Earth's atmosphere, while the rest are due to absorption in the Sun's → photosphere. C and F are now better known as H-alpha and H-beta (→ Balmer series); the → D lines are of sodium, the → H and K lines of calcium, and the G band of neutral iron and the interstellar → CH (methylidine) molecule.

Named after Joseph von Fraunhofer (1787-1826), German optician and physicist, who discovered these lines in 1814; → line.

Fraunhofer's refractor
  شکست‌گر ِ فراؤنهوفر   
šekastgar-e Fraunhofer

Fr.: réfracteur de Fraunhofer   

The first modern refracting telescope which had an outstanding quality. It was built in 1824 by Fraunhofer for the Russian Imperial Observatory in Dorpat, now Tartu in Estonia. It had a 23-cm → achromatic lens and a German-type → equatorial mounting driven by a clockwork. Wilhelm Struve (1793-1864) used the refractor to observe many → visual binaries, and attempted to measure the distances of stars through their visual → parallaxes. He also obtaibned accurate values for the diameters of the → Galilean satellites of → Jupiter.

Named after Joseph von Fraunhofer (1787-1826), German optician and physicist; → refractor.

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