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: 685
Dresden codex
  دستنوشت ِ درسدن   
dastnevešt-e Dresden (#)

Fr.: codex de Dresden   

A pre-Colombian Maya manuscript consisting of numerous calendar and astronomical data, probably dating from the 12th century. It seems that it is an updated copy of a document from the period of the old Maya Empire (4th-9th centuries). It contains a table which covers over 32 years, grouping 45 successive → lunations, divided into 69 groups of 5 or 6 lunations. The data are calculated in days and correspond remarkably to the intervals in an eclipse table: each group ends at the probable date of a solar eclipse (M.S.: SDE).

Dresden refers to the Dresden Library where the original document is preserved. It was bought in 1739 by the library director, Johann Christian Götze, who found it in a private library in Vienna. Its earlier history is unknown; codex, from L. codex earlier caudex "book, book of laws," literally "tree-trunk, book (formed originally from wooden tablets)."

Dastnevešt "handwritten," from dast, → hand, + nevešt "written," from neveštan "to write," → subscript.

drift
  ۱) دلک؛ ۲) دلکیدن   
1) delek; 2) delekidan

Fr.: 1) dérive; 2) dériver   

1a) General: A driving movement or force; impulse; impetus; pressure.
1b) Physics: A slight change of a quantity with time, for example the sensitivity of an electronic detector continuously operated during a long period as an effect of continued use.
1c) A slow change in frequency of a radio transmitter.
1d) Aerospace: The gradual deviation of a rocket or guided missile from its intended trajectory.
2) (v.intr.) To be carried along by currents of water or air, or by the force of circumstances.

From M.E. drift, from O.E. drifan "to drive," or from O.N. or M.Du. drift, from P.Gmc. *driftiz, related to *dribanan "to drive."

Delek from Lori, Laki, Hamadâni, Malâyeri "push, shove, drive;" variants Gilaki duko, Tâleši dako, Baluchi dhakkk(a) "push, shove, blow," Choresmian dh- "to hit," Kurd. dân/di- "to beat, hit," Proto-Iranian *daH- "to beat, hit, strike" (Cheung 2007); PIE base *dhen- "to hit, push;" delekidan, verb from delek.

drift curve
  خم ِ دلک   
xam-e delek

Fr.: courbe de passage   

In radio astronomy, the output response as a function of position for a given filter as the source passes through the beam.

drift; → curve.

drift rate
  نرخ ِ دلک   
nerx-e delek

Fr.: taux de dérive   

The amount of drift, in any of its several senses, per unit time.

drift; → rate.

drift velocity
  تندای ِ دلک   
tond-ye delek

Fr.: vitesse de dérive   

The average velocity of a charged particle in a plasma in response to an applied electric field.

drift; → velocity.

drive
  ۱) راندن؛ ۲) رانش، رانه   
1) rândan (#); 2) râneš (#), râné (#)

Fr.: 1) entraîner; 2) entraînement   

1a) To cause to move, to force to act. → continuum-driven wind, → dust-driven wind, → line-driven wind, → radiation-driven implosion, → radiation-driven mass loss, → radiation-driven wind.
1b) To cause and → guide the → motion of a → telescope.
2a) The act of driving.
2b) The → mechanism that imparts or transfers → power to a telescope so that it can move. → alpha drive, → delta drive, → drive accuracy, → slewing drive .

M.E. driven; O.E. drifan; cf. O.N. drifa, Goth. dreiban.

Rândan "to cause to go," causative of raftan "to go, walk, proceed" (present tense stem row-, Mid.Pers. raftan, raw-, Proto-Iranian *rab/f- "to go; to attack").

drive accuracy
  رشمندی ِ رانه   
rašmandi-ye râné

Fr.: précision de guidage   

The accuracy with which a telescope is moved by alpha or delta drives.

drive; → accuracy.

drizzle
  نرمه باران   
narmé bârân (#)

Fr.: bruine, crachin   

Very small, numerous, and uniformly distributed water drops that may appear to float while following air currents. Unlike fog droplets, drizzle falls to the ground.

Drizzle, dryseling "a falling of dew," from M.E. drysning, related to dreosan "to fall," cf. O.S. driosan, Goth. driusan.

Narmé bârân literally "smooth rain," from narmé, from narm "soft; smooth; mild," Mid.Pers. narm + bârân, → rain.

drop
  ۱) چکه؛ ۲) چکیدن   
1) cekké; 2) cekidan

Fr.: 1) goutte; 2) tomber goutte à goutte   

1a) A small quantity of liquid that falls or forms in a round or pear-shaped mass.
1b) A very small quantity of liquid; a very small quantity of anything.
2) To fall in small portions, as water or other liquid.

M.E. drop(e), from O.E. dropian; related to O.H.G. triofan, Du. drop, Ger. Tropfen.

Cekké, cekidan "drop; small, minute," cekidan "to drop."

droplet
  چکه، چکک   
cekké, cekkak

Fr.: gouttelette   

A very small drop of a liquid.

drop + diminutive suffix let.

Drummond light
  نور ِ درامن   
nur-e Drummond

Fr.: lumière de Drummond   

A very brilliant white light which is the ignited flame of a mixture of oxygen and hydrogen projected against a block of calcium oxide (lime). Also called limelight. First working version produced by Lieutenant of the Royal Engineers, upon the Ordnance Trigonometrical Survey of Ireland (1826). It was used at night as a substitute for solar light. It was first employed in a theater in 1837 and was in wide use by the 1860s, among which in photography.

Named after Scottish engineer Thomas Drummond (1797-1840); → light.

dry
  خشک   
xošk (#)

Fr.: sec, aride   

1) Lacking moisture; not damp or wet.
2) Having little or no rainfall.

M.E. drie; O.E. dryge; cf. M.L.G. dröge, M.Du. druge, Du. droog, O.H.G. trucchon, Ger. trocken.

Xošk "dry;" Mid.Pers. xušk "dry;" O.Pers. uška- "mainland;" Av. huška- "dry;" cf. Skt. śuska- "dry, dried out;" Gk. auos "dry, dried up;" O.E. sēar "dried up, withered;" Lith. sausas "dry, barren."

dry merger
  تشک ِ بی‌گاز   
tašk-e bigâz

Fr.: fusion sans gaz   

A merger between → gas-poor  → early-type galaxies.

dry; → merger.

dual
  دوگانه   
dogâné (#)

Fr.: double   

Of, pertaining to, or noting two; having a twofold, or double, character or nature.

From L. dualis, from duo "two."

Dogâné, from do "two," cognate with duo + -gân plurality suffix + nuance suffix.

dual supermassive black hole
  سیه‌چال ِ ابر-پرجرم ِ دوگانه   
siyah-câl-e abar-porjerm-e dogâné

Fr.: trou noir supermassif double   

The outcome of a → merger process between two galaxies, each with its own central → supermassive black hole (SMBH), resulting in a remnant galaxy hosting two SMBHs. Simulations of → galaxy mergers show there should be lots of dual → active galactic nuclei (AGN) visible at less than 10 kpc separations. As of 2015 more than 100 known dual supermassive black holes have been found. See also → binary supermassive black hole.

dual; → supermassive; → black; → hole.

duality
  دوگانگی   
dogânegi (#)

Fr.: dualité   

The quality or character of being twofold, as the → wave-particle duality.

M.E dualitie, from L.L. dualitas.

Dogânegi, from dogânag + -i.

Dubhe (α Ursae Majoris)
  دبه   
dobbé (#)

Fr.: Dubhé   

The second brightest star in the constellation → Ursa Major with a → visual magnitude of about 1.8. It lies at the front of the → Big Dipper's bowl and with → Merak (Beta UMa) makes the famous → Pointers. α Ursae Majoris is a → supergiant of type K0 IIIa and has a → companion.

From Ar. al-dubb (الدب) "bear," referring to the bear in Gk. mythology.

Dobbé from Ar., as above.

ductile
  رشایند   
rešâyand

Fr.: duvtile   

Describing a substance that exhibits → ductility.

M.E., from L. ductilis, from duct(us), p.p. of ducere "to draw along," → aonduct, + -ilis "-il," a suffix of adjectives.

Rešâyand, literally "capable of becoming string, thread," from reš, as in rešté "thread, line, rope, row," rešmé "string, rope, thread," variants rasan, ras, (Gilaki) viris, related to abrišam "silk;" from reštan, risidan "to spin;" Mid.Pers. rištag "rope, string, thread;" Av. uruuaēs- "to turn around," uruuaēsa- "vortex in water;" Proto-Iranian *uris- "to turn, spin;" cf. Skt. vréśī- "an appellation of waters;" Gk. rhiknos "crooked;" Lith. rišti "tie, bind;" O.H.G. rīho "knee-bend;" âyand agent noun form of âmadan "to come; to become," → elastic.

ductility
  رشایندی   
rešâyandi

Fr.: ductilité   

The property of a metal that allows it to be elongated into wire or threads without fracture. For example, → copper and → silver are highly ductile metals.

ductile; → -ity.

Dulong-Petit law
  قانون ِ دولون-پتی   
qânun-e Dulong-Petit

Fr.: loi de Dulong et Petit   

The product of the → specific heat and → atomic weight of most solid elements at room → temperature is nearly the same. In other words, specific heat is constant for a solid and independent of temperature. Experiment shows that at moderate temperatures this law is satisfied for → crystals with rather simple structure. However, the law fails for crystals with more complex structures. More specifically the law cannot explain the variation of specific heat with temperature. The specific heat drops to zero as the temperature approaches 0 K. This behavior is explained only with the quantum theory. → Debye model.

Named after Pierre L. Dulong (1785-1838) and Alexis T. Petit (1797-1820), French chemists, who proposed the law in 1819. They collaborated in several important investigations, including studies of thermal expansion of gases and of liquids and the specific heats of substances; → law.

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