An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



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Number of Results: 737
  مرتوگان زدودن   
martugân zodudan

Fr.: déshumaniser   

To deprive of → human qualities or personality.

de-; → dehumanize.

Deymos (#)

Fr.: Deimos   

The smaller and outermost of Mars' two satellites. It measures 12.6 km in size, and orbits Mars every 30.2 hours at a distance of about 23,500 km. It was discovered by the American astronomer Asaph Hall in 1877.

In Gk. mythology, Deimos, meaning "fear, terror," is one of the sons of Ares (Mars) and Aphrodite (Venus).


Fr.: désionisation   

Chemistry: A process in which all charged species are removed from a solution.
The return of an ionized gas to its non-ionized state after the ionizing source has been removed.

From → de- + → ionization.

  دادارباوری، ایزدباوری   
dâdâr-bâvari (#), izad-bâvari

Fr.: déisme   

1) Belief in the existence of a → God on the evidence of → reason and → nature only, with rejection of supernatural revelation (distinguished from → theism).
2) Belief in a God who created the world but has since remained indifferent to it (

From Fr. déisme, from L. de(us) "god," → deity, + → -ism.

Dâdâr-bâvari, from dâdâr "creator," → author, + bâvari, → ism; izad-bâvari, from izad "god," → deity.

  دادارباور، ایزدباور   
dâdâr-bâvar (#), izad-bâvar

Fr.: déiste   

A person who believes in → deism.

deism; → -ist

  ۱) ایزد؛ ۲) ایزدگان   
1) izad (#); 2) izadgân

Fr.: 1) dieu, déesse; 2) divinité   

1) A god or goddess.
2) Divine character or nature, especially that of the Supreme Being; divinity (

M.E. deite, from O.Fr., from L.L. deitat- (nominative deitas), from L. dei- (combining form of deus "god") + -tat- "-ty," formed after L. divinitas "divinity."

Izad "god;" from Mid.Pers. yazêt "god; angel," izišn "performance of the religious rites, worship," yašt "worship, religious ceremony," yaštan "to venerate, to perform the religious ceremony;" O.Pers. yad- "to worship;" Av. yaz- "to sacrifice, worship, venerate," yazata- "deities," yasna- "religious rite" (Mod.Pers. jašn "feast"); Proto-Ir. *iaz- "to sacrifice, worship, venerate."

del operator
  آپارگر ِ دل   
âpârgar-e del

Fr.: opérateur del   

In → vector calculus, a vector → partial derivative represented by the symbol → nabla and defined in three dimensions to be:
∇ = (∂/∂x)i + (∂/∂y)j + (∂/∂z)k.
It appears in the operations → gradient: ∇f, → divergence: ∇ . E, → curl: ∇ x E, and → Laplacian: ∇ . ∇f = ∇2f.

From Gk. alphabet letter delta.

derang (#)

Fr.: retard   

The amount of time by which an event is retarded.

From O.Fr. délaier, from dé-de- "away, from" + laiier, from laiss(i)er "to leave," from L. laxare "to loosen, release, set free."

Derang, from Mid.Pers. dirang, drang "delay, lateness; long, lasting," Av. drənj- "to fix, fasten, hold," Proto-Iranian *dra(n)j- "to fix, fasten, hold."

delay time
  زمان ِ درنگ   
zamân-e derang

Fr.: temps de retard, délai   

Same as → delay.

delay; → time.

delayed neutrons
  نوترونهای ِ درنگیده   
notronhâ-ye derangidé

Fr.: neutrons retardés   

Neutrons resulting from nuclear fission which are emitted with a measurable time delay. Delayed neutrons are responsible for the ability to control the rate at which power can rise in a reactor. → prompt neutrons.

Delayed, p.p. of the verbal form of → delay; → neutron.

delayed supernova explosion
  اسکفت ِ بادرنگ ِ اَبَر-نو‌اختر   
oskaft-e bâderang-e abar-now-axtar

Fr.: explosion retardée de supernova   

A mechanism predicted by theoretical models of → supernova explosion that operates after the → supernova shock fails to deliver a → prompt supernova explosion. The delayed supernova explosion mechanism assumes that a few tenth of a second after the → iron core collapse, the supernova shock is stalled due to energy dissipation. The material between the → protoneutron star and the stalled shock is mainly disintegrated into neutrons and protons due to the high temperatures (a few MeV) in this region. As the → neutrinos coming from the protoneutron star run through this material, a fraction of the neutrinos are captured by the → nucleons, and their energy is deposited in the material. As a result, the material behind the shock is heated by the neutrinos. If this neutrino heating is efficient enough, the stalled shock can be reinvigorated to bring about a supernova explosion.

delay; → supernova; → explosion.


Fr.: barrer, rayer   

To strike out or remove (something written or printed); cancel; erase.

L. deletus, p.p. of delere "destroy, blot out, efface," from delevi, fro delinere "to erase by smudging," from → de- "from, away" + linere "to smear, wipe."

Rušidan, from Kurd. rušê "to be wiped off through rubbing;" cf. Av. fra.uruxti- "destruction;" Wakhi riz-, rəz-/rəzd- "to tear apart, rip up a seam;" Yaghnobi ruc/ructa, rušta "to shave off the skin, skin off;" Proto-Ir. *rauj- "to break, bust" (Cheung 2007).


Fr.: suppression   

1) An act or instance of deleting. The state of being deleted. A deleted word, passage, etc.
2) Genetics: A type of chromosomal aberration in which a segment of the chromosome is removed or lost (

Verbal noun from → delete.


Fr.: délicat   

1) Fine in texture, quality, construction, etc.
2) Fragile; easily damaged; frail (

M.E. delicat, from L. delicatus "alluring, delightful, dainty," of uncertain origin.

Dârmé, from Mid.Pers. dârmag "delicate;" cf. (dialect of Ferdows) dermi "fine thread," Sogd. žâm, žam "delicate."

dolfin (#)

Fr.: Dauphin   

The Dolphin. A small northern constellation, lying just north of the celestial equator between → Pegasus and → Aquila. Abbreviation: Del;genitive: Delphini.

L. delphinus, from Gk. delphin-, delphis; akin to Gk. delphys womb, cf. Skt. garbha- "womb; interior."

Dolfin loanword from Gk.


Fr.: delta   

1) The fourth letter of the Greek alphabet (δ, Δ).
2) Anything triangular, like the Greek capital delta (δ).
3) Math.: An incremental change in a variable.

M.E. deltha, from L. delta, from Gk. delta; from the Phoenician name of the corresponding letter daleth "tent door."

Delta Cephei

Fr.: Delta Cephée   

The prototype of classical → Cepheid variables, which is a pulsating → yellow supergiant. John Goodricke was the first in 1784 to discover its variability. The star shows a quick and sharp rise from minimum to maximum, and slowly declines to its minimum again. The changes in brightness are accompanied by and principally caused by changes in stellar temperature and also by changes in radius. δ Cephei was actually the second Cepheid variable to be discovered. The first one, Eta Aquilae, had been discovered earlier the same year by Edward Pigott. δ Cephei varies with a period of 5.366341 days (or 5 days 8 hours 37.5 minutes) from magnitude 3.48, spectral type F5 Ib in its maximum to magnitude 4.37, spectral type G2 Ib in its minimum. It lies at a distance of 1,340 → light-years.

delta; Cephei, genitive of → Cepheus.

delta drive
  رانه‌ی ِ دلتا، ~ واکیل   
râne-ye deltâ , ~ vâkil

Fr.: entraînement en déclinaison   

The → mechanism that imparts or transfers power to a → telescope so that it can move along the → declination direction. See also → tracking.

delta; → drive.

delta function
  کریای ِ دلتا   
karyâ-ye delta

Fr.: fonction delta   

Same as → Dirac function.

delta offset
  اپنه ِ دلتا   
apneh-e deltâ

Fr.: offset en déclinaison   

A short distance from the target, in → declination, where the → telescope is pointed for various purposes.

delta; → offset.

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