An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



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Number of Results: 1327
convective vortex
  گردشار ِ همبزی   
gerdšâr-e hambazi

Fr.: tourbillon convectif   

A common feature of the atmosphere that ranges from small-scale → vortices such as → dust devils, to large-scale systems such as → cyclones.

convective; → vortex.

convective zone
  زنار ِ همبزی   
zonâr-e hambazi

Fr.: zone convective   

A zone inside a star in which → convection takes place; the central → core in → massive stars and the zone underneath → photosphere in low mass stars like the Sun. Recent works predict the presence of a thin convection zone in sufficiently massive main sequence stars which originates from the iron opacity and partial helium ionization. See also → iron convection zone.

convective; → zone.

hamgerâyidan (#)

Fr.: converger   

1) General: To tend to meet in a point; incline toward each other.
2) Math: (of an infinite series) to have a finite sum. (of an improper integral) to have a finite value.

From L.L. convergere "to incline together" from → com- "together" + vergere "to bend."

Hamgerâyidan, from ham- "together," → com- + gerâyidan "to incline toward, verge on; to intend," Mid.Pers. grayidan "to lean, incline; to intend, desire," → diverge.

hamgerâyi (#)

Fr.: convergence   

1) General: Act or state of converging.
2) Math: The property of a → sequence or → series which ensures that it will approach a definite → finite limit. See also: → divergence.

From converg-, from → convergent + -ence, equivalent to → -ance.

Hamgerâyi, verbal noun from hamgerâyidan, → converge.

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.


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.

  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.


Fr.: convertisseur   

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

convert; → -er.

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.


Fr.: convaincre   

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

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.


Fr.: convaincant   

Capable of causing someone to believe that something is true or real (

convince; → -ing.

  هم-وچ، هموچ   

Fr.: convocation   

The act of convoking. The state of being convoked.

Verbal noun of → convoke.

  هم-وچیدن، هموچیدن   

Fr.: convoquer   

To call together; summon to meet or assemble (

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.


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.


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).


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).

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