An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



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Number of Results: 706

Fr.: directeur   

A person who directs a project, a group, a production.

From → direct + -tor a suffix found in loanwords from L., forming personal agent nouns from verbs.

Râštâr, from râšt- stem of râštidandirect + -âr suffix of agent noun (as in parastâr "nurse").

Dirichlet condition
  بوتار ِ دیریکله   
butâr-e Dirichlet

Fr.: condition de Dirichlet   

One of the following conditions for a → Fourier series to converge:
1) The function f(x) is defined and single valued, except possibly at a finite number of points in the interval -π, +π.
2) f(x) has a period of 2π.
3) f(x) and f'(x) are → piecewise continuous functions on -π, +π.
Then, the Fourier series converges to:
(a) f(x) if x is a point of continuity.
(b) (f(x + 0) + f(x - 0))/2, if x is a point of discontinuity.

Named after Peter Gustav Lejeune Dirichlet (1805-1859), German mathematician who made valuable contributions to → number theory, → analysis, and → mechanics; → condition.

cerk (#)

Fr.: saleté   

A substance, such as mud or dust, that soils someone or something (

Metathesis of M.E. drit, drytt "mud, dirt, dung," from O.N. drit, cognate with O.E. dritan.

Cerk "dirt, filth."

cerkin (#)

Fr.: sal   

Covered or marked with an unclean substance. → dirty ice, → dirty iceball model.

dirt + suffix -y.

dirty ice
  یخ ِ چرکین   
yax-e cerkin

Fr.: glace sale   

Interstellar ice grains with graphite, silicates, or other chemical compounds adsorbed on their surfaces.

dirty; → ice.

dirty iceball model
  مدل ِ گلوله‌ی ِ یخ   
model-e golule-ye yax

Fr.: modèle de la boule de glace sale   

A model for a → cometary nucleus proposed by Fred Whipple (1950-51), according to which the nucleus is a solid body (a few kilometers across) made up of various → ices (→ frozen water, → methane, → ammonia, → carbon dioxide, and → hydrogen cyanide) in which → dust is embedded. Dust particles are liberated when the ices vaporize as the → comet approaches the → Sun, and they get blown away by → solar radiation pressure, often forming impressive, gently curved → dust tails.

dirty; → ice; → ball; → model.

vâ- (#)

Fr.: dis-   

A prefix meaning "lack of, not" (e.g. dishonest); "do the opposite of" (e.g. disallow); "apart, away" (e.g. discard); before f, dif-; before some consonants (b, d, l, m, n, r, s, v, and sometimes g and j) di-.

From O.Fr. des-, from L. dis- "apart," from PIE *dis- "apart, asunder" (cf. O.E. te-, O.S. ti-, O.H.G. ze-, Ger. zer-). The PIE root is a secondary form of *dwis- and is thus related to L. → bis "twice."

Vâ- prefix denoting "separation; repetition; open; reversal, opposition; off; away," variant of bâz-, from Mid.Pers. abâz-, apâc-; O.Pers. apa- [pref.] "away, from;" Av. apa- [pref.] "away, from," apaš [adv.] "toward the back;" cf. Skt. ápāñc "situated behind."


Fr.: desallouer   

Computers: To cancel the assignment of a particular resource to a user.

dis- + → allocate.


Fr.: desallouation   

The act of disallocating or the state of being disallocated.

dis- + → allocate.


Fr.: déapprobation   

The act or state of disapproving; a condemnatory feeling, look, or utterance.

dis-; → approval.


Fr.: désapprover   

To withhold approval from; decline to sanction.

dis-; → approve.


Fr.: décharge   

The removal or transference of an electric charge, as by the conversion of chemical energy to electrical energy.
The sudden and momentary equalization of a difference of potential, as between two terminals.

From M.E. deschargen, from O.Fr. deschargier "unload," from L.L. discarricare, from → dis- "do the opposite of" + carricare "to load a cart," from carrus "cart."

Vâbâr, from vâ- reversal prefix, → de- + bârcharge.

  هاوشانیگی، هاوشان‌مندی   
hâvešânigi, hâvešânmandi

Fr.: disciplinarité   

The quality or state of being → disciplinary.

disciplinary; → -ity.

  هاوشانی، هاوشان‌مند   
hâvešâni, hâvešânmand

Fr.: disciplinaire   

Of, for, or constituting a → discipline. See also → interdisciplinary, → multidisciplinary, and → transdisciplinary.

discipline; → -ary.


Fr.: discipline   

1) A branch of learning or instruction.
2) A system of rules for behavior, methods of practice, etc.

M.E., from M.Fr. discipline, descepline, from L. disciplina literally "teaching, instruction," from discipulus "pupil, student, follower," from dis- + cipere, combining form of capere "to take," → concept, + -ulus, → -ule.

Hâvešân, from hâveš "disciple, pupil," Mid.Pers. hâvišt "disciple, pupil;" Av. hāvišta- "disciple, pupil," + -ân a suffix denoting "group, order, system."

nâpeyvastegi (#)

Fr.: discontinuité   

A break in sequence or continuity of anything. → Balmer discontinuity
Math.: A point at which a function is not continuous.
Geology: A surface separating rock layers of differing properties or compositions.

M.L. discontinuitas, from discontinuus, from → dis- + continuus, → continuous.

Nâpeyvastegi, noun from nâpeyvasté "discontinuous," from nâ- "non, un-," → a-, + peyvasté, → continuous.

  پدواریدن، کشف کردن   
padvâridan, kašf kardan

Fr.: découvrir   

To find (something previously unseen or unknown) after study or search.

M.E. discoverir, descovrir, from O.Fr. descovrir "uncover, unveil, reveal," from L.L. discooperire, from L. → dis- "opposite of" + cooperire "to cover up," → cover.

Padvâridan "to uncover," infinitive from padvâr, from prefix pad- "against, contrary, opposite to," variants pat-, pâd-, → anti-, + vâr- "to cover;" cf. Av. vār- "to cover;" Mid.Pers. (with prefix *uz-) uzvâr- "to interprete, uncover, grasp," Pers. hozvâr(eš) "interpretation;" Khotanese (+ *ui-) gvir- "to be revealed;" Choresmian (+ *apa-) bw'rg- "to uncover;" Pers. barg "cover, clothes;" šalvâr "trousers" (Cheung, 2007).

  پدوار، پدوارش، کشف   
padvâr, padvâreš, kašf

Fr.: découverte   

The act or an instance of discovering. Something discovered.

Verbal noun of → discover.

nâhamxâni (#)

Fr.: écart, désaccord   

Divergence or disagreement, as between facts, claims, or calculations.

From L. discrepantia, from discrepantem, pr.p. of discrepare "sound differently, differ," from → dis- "apart, off" + crepare "to rattle, crack."

Nâhamxâni, from nâ- "non, un-," → a-, + hamxâni "siniging together," from ham- "together," → com-, + xâni, from xân stem of xândan "to sing; to read; to call," Mid.Pers. xwân- "to resound; to call," Av. xvan- "to sound," Proto-Iranian *huan- "to call;" cf. Skt. svan-, sváranti "to sound, make a sound, sing;" L. sonus "sound," sonare "to sound;" O.E. swinn "music, song," PIE base *suen- "to sound" (Cheung 2007).

  گسسته، جدا   
gosasté, jodâ (#)

Fr.: discret   

Apart or detached from others; separate; distinct. Composed of distinct or discontinuous elements.

From O.Fr. discret, from L. discretus "separated, distinct," from p.p. of discernere "to distinguish," from → dis- "off, away" + cernere "distinguish, separate, sift," → crisis.

Gosasté "broken, broken off," p.p. of gosastan "to break, split," Mid.Pers. wisistan "to break, split," Av. saed- "to split," asista- "unsplit, unharmed," Skt. chid- "to split, break, cut off," Gk. skhizein "to split," L. scindere "to split;" PIE stem *skei- "to split, cut."
Jodâ "separate, distinct," Mid.Pers. jutâk (yutâk), jut (yut).

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