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: 1244
Coal Sack
  گونی ِ زغال   
Guni-ye Zoqâl (#)

Fr.: sac de charbon   

A prominent → dark nebula visible to the naked eye as a dark patch silhouetted against the starry band of → Milky Way in the Southern sky. It obscures an area of about 5 by 7 degrees on the sky and extends beyond the borders of → Crux into neighboring → constellations → Centaurus and → Musca. It lies at a distance of approximately 500 → light-years.

coal; sack, from M.E., from O.E. sacc, from L. saccus, from Gk. sakkos, of Semitic origin (cf. Heb. saq "sack").

Guni "sack;" zoqâl, → charcoal.

coalesce
  آهمیدن   
âhamidan

Fr.: fusionner   

To grow together; to come together so as to form one whole, to fuse. → merge; → fusion.

From L. coalescere, from co- + al-, stem of alere "to nourish, make grow" + -esce, from -escere, a suffix conveying an inchoative meaning.

Âhamidan, from â- nuance prefix + ham "together" (Av. hama- "similar, the same;" Skt. samah "even, level, similar, identical;" Gk. hama "together with, at the same time," homos "one and the same," PIE *samos "same," from base *sem- "one, together") + -idan infinitive suffix.

coalescence
  آهمش   
âhameš

Fr.: coalescence   

1) General: The act or state of growing together, as similar parts; the act of uniting by natural affinity or attraction; the state of being united.
2) Merging of the stars composing a → binary system after having undergone → supernova explosion. General relativity predicts that binary systems of → compact objects will emit energy in the form of → gravitational radiation, and that this loss of energy eventually will lead to the coalescence of the system.

Verbal noun from → coalesce.

coalescence model
  مدل ِ آهمش   
model-e âhameš

Fr.: modèle de coalescence   

A scenario for building up → massive stars through merging of → intermediate-mass protostars. It occurs in the cores of dense stellar clusters that have undergone core contraction due to rapid → accretion of gas with low → specific angular momentum. The required densities are, however, very high, 108 stars pc-3, which are extremely rare (Bonnell et al. 1998, MNRAS 298, 93).

coalescence; → model.

coast
  رهارفتن   
rahâraftan

Fr.: accoster   

To move without further use of propelling power. → coasting flight, → coasting Universe.

M.E. coste, from O.Fr., from L. costa "rib, side," cf. Mid.Pers. kust, kustag "side, direction; district," Mod.Pers. xost, xwast "a beaten road; island;" PIE *kost- "leg, bone."

Rahâraftan, from rahâ "free, set free" (O.Pers. rad- "to leave," Skt. rah-, rahati "separates, leaves," Av. razah- "isolation;" PIE *redh-) + raftan "to go, walk" (Mid.Pers. raftan, raw-, Proto-Iranian *rab/f- "to go; to attack").

coasting flight
  پرواز ِ رهارو   
parvâz-e rahârow

Fr.: vol d'accostage   

The unpowered flight of a spacecraft or missile after propulsion cutoff or between the burnout of one stage and the ignition of the next.

Coasting, verbal adjective from → coast; → flight.

coasting Universe
  گیتی ِ رهارو   
giti-ye rahârow

Fr.: Univers à densité critique   

A Universe whose density is just less than or equal to the critical value and expands forever with no change in the expansion rate.

Coasting, verbal adjective from → coast; → Universe.

coat
  اندودن   
andudan (#)

Fr.: revêtir, couvrir   

To → cover with a → thin  → layer of a → substance, as → aluminum over the → surface of a → mirror, → aluminize.

Verb from noun coat, from M.E. cote, from O.Fr. cote "coat, robe," from some Germanic source; cf. O.S. kot "woolen mantle," O.H.G. chozza "cloak of coarse wool," Ger. Kotze "a coarse coat," of unknown origin.

Andudan, variant andâyidan, from Mid.Pers. handudan, from O.Iranian *ham-dâvaya-, from ham- "together" + *dâvaya-, from dav- "to rub, clear," cf. Av. dav- "to clean, polish," Skt. dhâv-, PIE *dheu- "to shine".

Coathanger
  رخت‌آویز   
raxtâviz (#)

Fr.: amas du Cintre   

An open cluster of about 40 stars at the border of → Vulpecula and → Sagitta. It has an apparent size of about 1° and lies 420 → light-years away. Also called Collinder 399 and → Brocchi's Cluster. Six of its brighter stars, of sixth and seventh magnitude, are lined up in a nearly perfect row, from the center of which four stars form a hook to resemble the coathanger shape. To the naked eye, it appears as an unresolved patch first recorded by the Persian astronomer Sufi in A.D. 964. It was later rediscovered by Giovanni Battista Hodierna (1597-1660). The Coathanger shares roughly the same motion with several other clusters, including the → Pleiades.

coat; hanger, from hang, M.E. han(i)gen, fusion of O.E. hon "suspend" and hangian "be suspended;" also probably influenced by O.N. hengja "suspend" and hanga "be suspended" (cf. O.Frisian hangia, Du. hangen, Germ. hängen).

Raxtâviz, from raxt "clothes, garment, wearing apparel" + âviz "hang," → pendulum.

coating
  اندود   
andud (#)

Fr.: revêtement   

A → thin → layer of a → substance spread over a → surface.

Noun from → coat; → -ing.

cobalt
  کوبالت   
kobâlt (#)

Fr.: cobalt   

A silver gray, brittle, hard metallic → chemical element which is highly magnetic; symbol Co. → Atomic number 27; → atomic weight 58.9332; → melting point 1,495°C; → boiling point about 2,870°C; → specific gravity 8.9 at 20°C. It is used in many → alloys, and in particular its compounds have been used since ancient times (Egyptians, Persians, Greeks) to produce a blue color in glass and ceramics. Cobalt was discovered in 1735 by the Swedish chemist Georg Brandt (1694-1768). It has several radioactive isotopes, including Co-56, half-life about 77 days, Co-57, 272 days, Co-58, 71 days, Co-60, 5.27 years. The → light curve of → type I supernovae is explained by the radioactive decay of nickel-56 through cobalt-56 to iron-56.

From Ger. kobold "evil spirits or goblins," who were superstitiously thought to cause trouble for miners, since the mineral contained arsenic which injured their health and the metallic ores did not yield metals when treated with the normal methods.

cobweb
  کرو، کاتنه   
karu (#), kâtené (#)

Fr.: toile d'arraignée   

A web spun by a spider to entrap its prey; a single thread spun by a spider; something resembling a cobweb; anything finespun, flimsy, or insubstantial (Dictionary.com).

M.E. coppeweb, derivative of O.E. -coppe "spider" in atorcoppe "poison spider;" + → web.

Karu "cobweb, web," variants kari, kartané, kartiné, kârtanak, kârtané, kare tan (all in Dehxodâ), (Malâyeri, Hamadâni) kâtena, (Gilaki) kârtang, (Kermâni) kerâš, (Qêyeni) kalaš, (Qomi) kârye, (Tabari) kel, kuli, (Yazdi) kare, from *kar-, *kâr-, *kel- "to weave;" cf. (Ormuri, in Pakistan, Afghanistan) gal-/galôk- "to weave;" PIE base *ker- "to weave; rope."

Cocoon Nebula (IC 5146)
  میغ ِ پیله   
miq-e pilé

Fr.: nébuleuse du cocon   

An emission nebula located about 3,000 light-years away toward the → constellation  → Cygnus. It is thought to be a region of active → star formation.

Cocoon, from Provençal Fr. coucoun, from O.Fr. coque "egg shell, nut shell," L. coccum "berry," from Gk. kokkos "berry, seed;" → star; → nebula.

Miq, → nebula; pilé "the silkworm's cocoon; a purse", cf. Skt. patta- "woven silk."

cocoon star
  ستاره‌ی ِ پیله‌ای   
setâre-ye pileyi

Fr.: étoile dans son cocon   

A star hidden in a dense envelope of gas and dust which is a strong source of infrared emission.

Cocoon nebula; → star.

code
  رمز   
ramz (#)

Fr.: code   

1) A system used for brevity or secrecy of communication, in which arbitrarily chosen words, letters, or symbols are assigned definite meanings.
2) Computers: The symbolic arrangement of statements or instructions in a computer program in which letters, digits, etc. are represented as binary numbers; the set of instructions in such a program (Dictionary.com).

M.E., from O.Fr. code, from L. codex "book, book of laws," later form of caudex "tree trunk," hence "document made up of wooden tablets."

Ramz "secret writing, enigma," loan from Ar.

codeclination
  هم‌واکیلش   
hamvâkileš

Fr.: codéclinaison   

The complement of → declination; the angular distance along a great circle from the celestial pole, i.e., 90° - declination.

Codeclination, from → co- + → declination.

Hamvâkil, from ham-, → co-, + vâkil, → declination.

codomain
  هم-دمن   
ham-daman

Fr.: ensemble d'arrivée   

The set of values that a → function is allowed to take (i.e. may possibly come out of a function), as opposed to the → range.

co-; → domain.

coefficient
  همگر   
hamgar (#)

Fr.: coefficient   

1) Math.: A number or letter placed before an algebraic expression to indicate that the expression is to be multiplied by that factor, e.g. in the expression 2 x3, 2 is the coefficient of x3. In general, any factor of a product is called the coefficient of the product of the remaining factors.
2) Physics: Factor which measures some specified property of a given substance, and is constant for that substance under given conditions, such as the coefficient of friction. → factor.

Hamgar, from ham- "together," → com- + -gar agent suffix, from kar-, kardan "to do, to make," Mid.Pers. kardan, O.Pers./Av. kar- "to do, make, build," Av. kərənaoiti "makes," cf. Skt. kr- "to do, to make," krnoti "makes," karma "act, deed;" PIE base kwer- "to do, to make."

coefficient of viscosity
  همگر ِ وشکسانی   
hamgar-e vošksâni

Fr.: coefficient de viscosité   

A quantity that indicates a property of fluids and is defined by the ratio of shearing → stress to the rate of change of shearing → strain. It is also simply called viscosity. The coefficient of viscosity is expressed by: μ = (F/A) / (dv/dy), where F is the force required to maintain a steady velocity difference dv between any two parallel layers of the fluid, A is the area of the layers, and dv/dy is the → velocity gradient between two points separated by a small distance measured at right angles to the direction of flow. The unit of viscosity is that of force times distance divided by area times velocity. Thus, in the cgs system, the unit is 1 dyne.cm/cm2.(cm/s), which reduces to 1 dyne.s/cm2. This unit is called 1 → poise.

viscosity; → coefficient.

coelostat
  آسمان داشتار   
âsmândâštâr

Fr.: coelestat   

A flat mirror with a clock-drive mounted in such a way that it moves from east to west to compensate for the apparent rotation of the Earth in order that the image of a particular area of sky remains fixed in the focal plane. See also → siderostat and → heliostat.

Coelostat, from L. coelo-, for caeli-, combination form of coelum "sky" + -stat prefix denoting something that stabilizes, keeps, fixes, from -stata, from Gk. -states "one that causes to stand," or statos "standing," from *sta- "to stand."

Âsmândâštâr, from âsmân, → sky, + dâštâr "holder, maintainer," from dâštan "to hold, maintain; to have; to possess," Mid.Pers. dâštan, O.Pers./Av. root dar- "to hold, keep back, maitain, keep in mind," Skt. dhr-, dharma- "law," Gk. thronos "elevated seat, throne," L. firmus "firm, stable," Lith. daryti "to make," PIE *dher- "to hold, support."

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