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: 1295
convergent
  همگرا   
hamgerâ (#)

Fr.: convergent   

Coming together, as a light beam after passing through a convex lens which brings the beam into the focus.

Verbal ddj. from → converge.

converging mirror
  آینه‌ی ِ همگرا   
âyene-ye hamgerâ (#)

Fr.: miroir convergent   

A concave mirror that reflects a parallel beam into a convergent beam.

From → converge + → -ing; → mirror.

conversion
  هاگرد   
hâgard

Fr.: conversion   

The act or process of converting; state of being converted. → convert.

Verbal noun of → convert.

Hâgard, from hâ- prefix denoting "reversal; to," sometimes creating nuance [Dehxodâ], + gard present stem of gardidan, gaštan "to change; to turn;" Mid.Pers. vartitan; Av. varət- "to turn, revolve;" cf. Skt. vrt- "to turn, roll," vartate "it turns round, rolls;" L. vertere "to turn;" O.H.G. werden "to become;" PIE base *wer- "to turn, bend."

conversion factor
  کروند ِ هاگرد   
karvand-e hâgard

Fr.: facteur de conversion   

1) A numerical factor that, by multiplication or division, translates one unit or value into another.
2) In → molecular cloud studies, a factor used to convert the → carbon monoxide (CO) line intensity to → molecular hydrogen (H2) → column density; usually denoted XCO = I(CO) / N(H2). This useful factor relates the observed CO intensity to the cloud mass. A general method to derive XCO is to compare the → virial mass and the 12CO (J = 1-0) luminosity of a cloud. The basic assumptions are that the CO and H2 clouds are co-extensive, and molecular clouds obey the → virial theorem. However, if the molecular cloud is subject to ultraviolet radiation, selective → photodissociation may take place, which will change the situation. Moreover, molecular clouds may not be in → virial equilibrium. To be in virial equilibrium molecular clouds must have enough mass, greater than about 105 solar masses. The way → metallicity affects XCO is a matter of debate, and there is no clear correlation between XCO and metallicity. Although lower metallicity brings about higher ultraviolet fields than in the solar vicinity, other factors appear to be as important as metallicity for the determination of XCO. In the case of the → Magellanic Clouds, XCO(SMC) = 14 ± 3 × 1020 cm-2 (K km s-1)-1, which is larger than XCO (LMC) = 7 ± 2 × 1020 cm-2 (K km s-1)-1. An independent method to derive XCO is to make use of the gamma ray emission from a cloud. The flow of → cosmic ray protons interacts with interstellar low-energy hydrogen nuclei in clouds creating neutral → pions. These pions quickly decay into two gamma rays. It is therefore possible to estimate the number of hydrogen nuclei and hence the cloud mass from the gamma ray counts. Such a gamma-ray based conversion factor is estimated to be 2.0 × 1020 cm-2 (K km s-1)-1 for Galactic clouds, in good agreement with the result obtained from the virial method. However, the gamma ray flux is not well known in general, so this method is uncertain as well. See, e.g., Fukui & Kawamura, 2010 (ARAA 48, 547).

conversion; → factor.

convert
  هاگرد کردن   
hâgard kardan

Fr.: convertir   

1) To change units of one measuring or calculating system into units of another.
2) To transform from one material or state to another.

M.E. converten, O.Fr. convertir, from L. convertere "to turn around, transform," from → com- "together" + vertere "to turn;" cognate with Mod.Pers. gardidan "to change, to turn," → conversion.

Compound verb from hâgard, → conversion, + kardan "to do, to make," → -ize.

converter
  هاگردگر   
hâgardgar

Fr.: convertisseur   

A device that receives data in one form and converts it to another. → analog-to-digital converter.

convert; → -er.

convex
  کوژ   
kuž (#)

Fr.: convexe   

Having a surface that is curved or rounded outward.

From M.Fr. convexe, from L. convexus "vaulted, arched," p.p. of convehere "to bring together," from → com- "together" + vehere "to bring" (cf. Skt. vah- "to carry, lead," vahitra "vehicle," Av. vazaiti "to lead," Mid.Pers. waz-, wazidan "to carry away," Gk. oxos "chariot," PIE base *wegh- "to go, carry, drive").

Kuž "humped," Mid.Pers. kôf "hill, mountain; hump" (Mod.Pers. kuh, "mountain"), kôfik "humpbacked," O.Pers. kaufa-, Av. kaofa- "mountain."

convex lens
  عدسی ِ کوژ   
adasi-ye kuž (#)

Fr.: lentille convexe   

A lens that converges an incident beam of light to a focus.

convex; → lens.

convince
  پروخیدن   
paruxidan

Fr.: convaincre   

To move by argument or evidence to belief, agreement, consent, or a course of action (Dictionary.com).

From L. convincere "to overcome decisively," from the intensive prefix → com- + vincere "to conquer, overcome, defeat," from PIE root *weik- "to fight, conquer."

Paruxidan, from Parthian Mid.Pers. prywx- "to conquer, overcome," from prefix pari- + yux "yoke;" Av. yuj- "to harness, yoke," variants yuj, juh, jut, jot; Mid.Pers. jug, ayoxtan "to join, yoke;" Pers. (+*pari-) piruz, pêrôz "victorious," → yoke.

convincing
  پروخنده   
paruxandé

Fr.: convaincant   

Capable of causing someone to believe that something is true or real (OxfordDictionaries.com).

convince; → -ing.

convocation
  هم-وچ، هموچ   
hamvac

Fr.: convocation   

The act of convoking. The state of being convoked.

Verbal noun of → convoke.

convoke
  هم-وچیدن، هموچیدن   
hamvacidan

Fr.: convoquer   

To call together; summon to meet or assemble (Dictionary.com).

M.E., from M.Fr. convoquer, from L. convocare "to call together," from → con- "together," + vocare "to call," from vox, → voice.

Hamvacidan, from ham-, → com-, + vac "word," → voice, + -idan infinitive suffix.

convolution
  هماگیش   
hamâgiš

Fr.: convolution   

1) A mathematical combination of two functions which involves multiplying the value of one function at a given point with the value of another function, the weighting function, for a displacement from that point and then integrating over all such displacements. The process is repeated for every point of the function. Convolution expresses how the shape of a function is altered by the other. In mathematical terms, the convolution of two functions f(x) and g(x) is defined by: f*g = ∫f(u)g(x - u) du, integral from -∞ to +∞.
2) Astro.: Convolution describes how an instrument, through its transfer function, affects an input signal. → deconvolution.

Verbal noun of → convolve.

convolution theorem
  فربین ِ هماگیش   
farbin-e hamâgiš

Fr.: théorème de convolution   

A theorem stating that the → Fourier transform of the convolution of f(x) and g(x) is equal to the product of the Fourier transform of f(x) and g(x): F{f*g} = F{f}.F{g}.

convolution; → theorem.

convolve
  هماگیشیدن   
hamâgišidan

Fr.: convoluer   

1) To roll or wind together.
2) To bring about a → convolution.

From L. convolvere "to roll together," from → com- "together" + volvere "to roll, turn," PIE base *wel- "to turn, revolve;" cf. Skt. valati "he turns," ulba- "womb, vulva," Gk. eilyein "to roll, wrap, fold."

Hamâgiš, from ham- "together", → com-, + âgišidan "to entwine, to twist" (Dehxodâ), from Mid.Pers. gyš- "to bind, tie," hangyš- "to fasten to;" cf. Sogd. patigyš- "to imprison, confine;" Proto-Ir. *kaš- "to imprison" (Cheung 2007).

cookie
  کوکی   
cookie

Fr.: cookie   

An identifier file that a website automatically places in the user's computer hard drive. The cookie is used by the website to identify that a user has been on the website previously. Users concerned about privacy may disable cookies in their browser's setting.

From Du. koekje "little cake," diminutive of koek "cake," from M.Du. koke, akin to cake, M.E., from O.N. kaka (O.H.G. kuocho "cake"), any relation with Pers. kâk "biscuit; dry bread"? (loaned in Ar. ka'k).

cool
  سرد   
sard (#)

Fr.: froid   

Moderately cold.

M.E., from O.E. col, PIE base *gel- "cold, to freeze."

Sard "cold, cool," from Mid.Pers. sart, Av. sarəta- "cold," Skt. śiśira- "cold," Ossetian sald "cold," L. calidus "warm," Lith. šaltas "cold," Welsh clyd "warm," PIE *keltos- "cool".

cool hypergiant
  هیپرغول ِ سرد   
hiperqul-e sard

Fr.: hypergéante froide   

A highly unstable, → very massive star lying just below the empirical upper luminosity boundary in the → H-R diagram (→ Humphreys-Davidson limit) with spectral types ranging from late A to M. Cool hypergiants very likely represent a very short-lived evolutionary stage, and are distinguished by their high → mass loss rates. Many of them also show photometric and spectroscopic variability, and some have large → infrared excesses and extensive circumstellar ejecta. The evolutionary state of most of these stars is not known but they are all → post-main-sequence stars (Humphreys, 2008, IAUS 250).

cool; → hypergiant.

coolant
  سردگر   
sardgar

Fr.: refroidissant   

An agent of → cooling process.

cooling.

cooling
  ۱) سردش؛ ۲) سردکننده، سردگر   
1) sardeš; 2) sardkonandé, sardgar

Fr.: 1) refroidissement; 2) refroidissant   

1) The process of losing heat; a falling temperature.
2) The participial adjective of to cool.

cool; → -ing.

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