An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



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Number of Results: 685
dependent variable
  ورتنده‌ی ِ وابسته   
vartande-ye vâbasté

Fr.: variable dépendante   

Math.: A variable whose value depends on the value assigned to another value. For example, in the equation y = 2x, the value of y depends on that of x. See also → independent variable.

dependent; → variable.


Fr.: déphaser   

To make two signals out of phase. For example, to get one signal at its highest peak while the other signal is at its lowest peak; they will be 180 degrees out of phase.

de-; → phase.


Fr.: déphasé   

Same as → out of phase.

Past participle of → dephase.


Fr.: amenuiser, réduire   

To decrease markedly the supply or abundance of; exhaust; to cause → depletion.

From L.L. depletionem "blood-letting," from L. deplere "to un-fill, to empty out," from → de- "off, away" + plere "to fill," from plenus "full," from PIE *ple- "to be full," PIE base *pelu- "full," cf. O.Pers. paru- "much, many," Av. parav-, pauru-, pouru-, par- "to fill," Mod.Pers. por "full," Skt. puru-, Gk. polus. por "full," Gk. polus, O.E. full "full," from P.Gmc. *fullaz, O.H.G. fol, Ger. voll, Goth. full.

Tisâyidan, from Tabari tisâ "empty, naked, bare" + -idan infinitive suffix. Variants of tisâ in dialects and literary Pers.: Saraxsi, Lâsgardi, Sangesari tusâ "empty, naked," Aftari tussâ "empty," literary Pers. tohi "empty," Mid.Pers. tuhig, Av. taoš- "to become empty," pres. tusa-, caus. taošaya-, tusən "they lose their posture," Skt. tuccha-, tucchya- "empty," L. tesqua, tesca "deserted place," Russian tošcij "hollow;" PIE base *teus- "to empty."


Fr.: déplétion   

General: The act or process of depleting. The state of being depleted.
Astro.: The process or state of a material which contains less of a particular chemical element or isotope than the expected standard amount.

Noun from → deplete

depletion layer
  لایه‌ی ِ تیسایش   
lâye-ye tisâyeš

Fr.: couche de déplétion   

The region of a semiconductor in which the density of mobile carriers is too low to neutralize the fixed charge density of donors and acceptors.

depletion; → layer.

depletion time
  زمان ِ تیسایش   
zamân-e tisâyeš

Fr.: temps de déplétion   

The time it takes for a given → chemical species to be reduced below a significant level of → abundance in a → compound or → object.

depletion; → time.

vâqotbeš (#)

Fr.: dépolarisation   

Reducing or randomizing the polarization of an electromagnetic wave, by transmission through a non-homogeneous medium or a depolarizer.

from → de- + → polarization.


Fr.: dépuepler   

To remove or reduce the population of, as by destruction or expulsion (

de-; → populate.

  ۱) لرد؛ ۲) لرد انداختن، ~ افتادن، لردیدن   
1) lerd; 2) lerd anxtan, lerd oftâdan, lerdidan

Fr.: 1) dépôt, gisement, lie, tarte; 2) déposer, se déposer   

1a) Something precipitated, delivered and left, thrown down, or accumulated, as by a natural process.
1b) Substance which settles down from a solution or a suspension, such as the natural sediment of wine in a bottle. See also → sediment.
2) To leave or form a layer of some substance (sand, sediment, etc.) as a gradual process in one place, or be left in this way.

From L. depositus, p.p. of deponere "to lay aside, put down," from → de- "away" + ponere "to put," → position.

Lerd "sediment, tartar of wine," probably a variant of dord "dregs, lees, sediment, tartar of wine."


Fr.: dépôt   

The process by which water vapor changes directly to ice without first becoming a liquid. This is how snow forms in clouds, as well as frost and hoar frost on the ground. The opposite of deposition is → sublimation. → condensation.

M.E., from O.Fr. deposition, from L. deposition- "putting aside, testimony, burial," from deposit(us) "laid down," p.p. of deponere "to put down," from → de- + ponere "to put, place."

Vâneheš, from vâ-de- + neheš verbal noun of nehâdan "to put, place," Mid.Pers. nihâtan, O.Pers./Av. ni- "down; into," → ni-, + dā- "to put; to establish; to give," dadāiti "he gives," cf. Skt. dadâti "he gives," Gk. didomi "I give," L. do "I give;" PIE base *do- "to give."

  ۱) نشیب ِ افق؛ ۲) فروبار؛ ۳) نشیب‌لاخ   
1) našib-e ofoq; 2) forubâr; 3)

Fr.: dépression   

1) Navigation:dip.
2) Meteorology: An area of low atmospheric pressure.
3) Geology: An area of the Earth's crust sunken or depressed below the surrounding area, formed by various mechanisms.

Depression, verbal noun of depress, from O.Fr. depresser, from L.L. depressare, frequentative of pressus, p.p. of deprimere "press down," from → de- "down" + premere "to press."

1) Našib-e ofoq, from našib "declivity, descent; lowness of ground, slope of any place" (Mid.Pers. nišēp "declivity, (astrology) dejection," Av. *nixšvaēpā-, xšvaēpā- "bottom, rear") + ofoqhorizon. 2) Forubâr, from foru "down, downward; below; beneath," → de- + bâr "load, pressure, charge," → charge. 3) Našiblâx, from našib, as above, in item 1, + -lâx place suffix.


Fr.: priver   

To remove or withhold something from the enjoyment or possession of (

M.E. depriven, from O.Fr. depriver, from L. deprivare, from → de- + privare "to separate, rob," → private

Âzvandan, from âz- "out, away," → ex-, + van, contraction of vand, band "to bind, fasten, close," → private.

žarfâ (#)

Fr.: profondeur   

Noun form of → deep. → optical depth.

From M.E. depthe, from O.E. deop "deep," → deep + -the "-th."

Žarfâ, noun of žarf "deep," → deep + .


Fr.: dérivation   

1) General: The act or fact of deriving or being derived; origin; descent.
2) Math.:differentiation; development of a theorem.
3) Grammar: The formation of a word from another word or base. It typically occurs by the addition of an affix.

Verbal noun of → derive.


Fr.: dérivé   

1) General: Derived from another; not original or primitive.
2) Math.: For a → function  y = f(x), the → limit of the → ratio of the → increment of the function, Δy, to the increment of the → variable, Δx, as the latter tends to → zero. Derived function; result of → differentiation.
3) Chemistry: Substance derived or prepared from some other → substance.

From M.E. derivatif, from L.L. derivativus, from derivat(us), p.p. of derivare, → derive + -ivus.

Vâxané, noun from vâxan, present stem of vâxanidan, → derive.


Fr.: dériver de, tirer de   

1) General: To conduct, draw, obtain from a source or origin; to trace to an origin.
2) Chemistry: To produce or obtain (a → substance) from another.
3) Math.: Verbal form of → derivation.

From O.Fr. dériver, from L. derivare "to draw off (a stream of water), from its source," from de- "from" + riv(us) "a stream" + -are infinitive suffix.

Vâxanidan, from vâ- prefix which indicates "returning to, reference," → de-, + xan "source," variant xân (Gilaki xoni, Tabari xoni, Laki kyani, Tâleši xâni, xoni, Mid.Pers. xân, xânig "source, spring," Av. xā-, xan- "source, fountain, spring," xayana- "belonging to a spring," cf. Khotanese khâhâ- "spring, fountain," Skt. khâ'- "spring, source") + -idan infinitive suffix.


Fr.: dérivé   

Determined by mathematical computation; formed or developed from something else; not original.

P.p. of → derive.

Descartes ray
  پرتو ِ دکارت   
partow-e Descartes

Fr.: rayon de Descartes   

Same as → rainbow ray.

Named after René Descartes (1596-1650), French mathematician, physicist, and philosopher, who made valuable contributions to the field of optics, and first calculated the angular radius of rainbows; → rainbow angle.

descending node
  گره ِ فرودشی   
gereh-e forudeši

Fr.: nœud descendant   

The point in an orbit where the orbiting body crosses a reference plane, such as the ecliptic or the celestial equator, going from north to south. → ascending node.

Descending, from descend, from L. descendere "to go down," from → de- "down" + scandere "to climb;" Node, from L. nodus "knot."

Gereh "knot," from Mid.Pers. grih "knot." Forudeši adj. of forudeš, verbal noun of forudidan "to descend, go down," (Mid.Pers. frôtihitan "to descend"), from forud "down, downward," Mid.Pers. frôt "down, downward," O.Pers. fravata "forward, downward," Skt. pravát- "a sloping path, the slope of a mountain."

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