An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



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Number of Results: 378
old stellar population
  پرینش ِ ستاره‌ای ِ کهن   
porineš-e setâre-yi-ye kohan

Fr.: population stellaire vielle   

A population of stars in a stellar system that have definitely left the → main sequence.

old; → stellar; → population.

olivin (#)

Fr.: olivine   

A silicate mineral of magnesium (Mg2SiO4) and iron (Fe2SiO4,) found commonly in basalt and in carbonaceous chondrites.

From Ger. Olivin, from olive, because of its olive-green to gray-green color, + -in equivalent to -ine a noun suffix used in chemical and mineralogical nomenclature.

Olympus Mons
  کوهِ اُلومپوس   
kuh-e Olumpos

Fr.: Olympus Mons   

The highest peak on Mars, and the largest volcano in the solar system. It rises to a height of 27 kilometres above the datum level selected on the basis of atmospheric pressure.This gigantic shield volcano, 700 kilometres across, is similar in nature to volcanoes on Earth but its volume is at least fifty times greater than its nearest terrestrial equivalent.

From L. Mons, → mountain, + Olympus, from Gk. Olympos a mountain (2966 m) in north-east Greece, on the boundary between Thessaly and Macedonia, mythical abode of the greater Grecian gods.

Omega Centauri (ω Cen)
  ا ُمگا کنتاؤروس   
Omegâ Kentawros

Fr.: Omega centauri   

The largest and most luminous → globular cluster associated with the Milky Way Galaxy. Omega Centauri is located about 18,300 → light-years away and contains several million old stars. The stars in its center are so crowded that they are believed to be only 0.1 light-year away from each other. It is about 12 billion years old. Omega Centauri was first listed in Ptolemy's catalog nearly two thousand years ago. In 1677 Edmond Halley reported it as a nebula, and in the 1830s John Herschel was the first to correctly identify it as a globular cluster. Also called NGC 5139.

Omega, Gk. alphabet letter; Centauri, → Centaurus.

omega effect
  اسکر ِ امگا   
oskar-e omega

Fr.: effet ω   

In the → solar dynamo model, the process whereby the → meridional magnetic field is stretched into an → azimuthal magnetic field by → differential rotation. See also → alpha effect.

Omega (ω), Gk. letter of alphabet; → effect.

Omega Nebula
  میغِ اُمگا   
miq-e omegâ

Fr.: nébuleuse Omega   

An → H II region located in the rich star fields of the → Sagittarius area of the Milky Way. Its distance from the Earth is between 5,000 and 6,000 → light-years and spans some 15 light-years in diameter. Its other designations are: Swan Nebula, Messier 17, and NGC 6618.

Omega, Gk. alphabet letter; → nebula.

Omicron Ceti
  ا ُمیکرون کتوس   
Omikron Ketus

Fr.: Omicron Ceti   

Another name for → Mira.

Omicron, Gk. alphabet letter; Ceti, → Cetus.

visp- (#)

Fr.: omni-   

All, universally.

L. omni-, combining form of omnis "all, every," of unknown origin.

Visp-, from Mid.Pers. visp- "all;" O.Pers. visa-, vispa- "all;" Av. vīspa- "all, every, entire, universal" (vīspô.ayāra- "lasting all the days," vīspô.vīδvah- "knowing everything, omniscient"); cf. Skt. vīśva- "all, every; whole, universal."

visp-tavân (#)

Fr.: omnipotent   

Having very great or unlimited power or authority.

omni-; → power.

  ویسپ‌باشنده، ویسپ‌باش، ویسپ‌باشا   
visp-bâšandé, visp-bâš, visp-bâšâ

Fr.: omniprésent   

Same as → ubiquitous.

omni-; → present.

  ویسپ‌دانا، ویسپ‌آگاه   
visp-dânâ (#), visp-âgâh (#)

Fr.: omniscient   

Having infinite knowledge, awareness, understanding, or insight.

omni-; L. scient "knowing," → science.

Visp-, → omni-, dânâ "knowing, learned," → science; âgâh "aware," → look.

bar- (#), dar- (#)

Fr.: sur   

Adverb, used as prefix denoting "in, into, onto; toward; with continuous activity," etc.

O.E. on, variant of an "in, on, into," from P.Gmc. (cf. Du. aan, Ger. an, Goth. ana "on, upon"), from PIE base *ano "on" (cf. Av. ana "on," Gk. ana "on, upon," L. an-, O.C.S. na, Lith. nuo "down from").

Bar "on; up; upon; in; into; at; forth; with; near; before; according to" (Mid.Pers. abar; O.Pers. upariy "above; over, upon, according to;" Av. upairi "above, over," upairi.zəma- "located above the earth;" cf. Gk. hyper- "over, above;" L. super-; O.H.G. ubir "over;" PIE base *uper "over").
Dar- "in," from Mid.Pers. andar, → intra-.


Fr.: en ligne   

The state when two or more devices are directly connected and are communicating efficiently.
Of computers, operating under the direct control of, or connected to, a main computer.

on; → line.

on-line reduction
  باز‌هازشِ بر-خط   
bâzhâzeš-e bar-xatt

Fr.: réduction enligne   

Preliminary reduction of observational data at a telescope simultaneously with their acquisition.

on-line; → reduction.

on-source observation
  نپاهشِ بر-خن   
nepâheš-e bar-xan

Fr.: observation sur la source   

In comparison with → off-source observation, an observation which is concerned with the source itself.

on-; → dource; → observation.

on-the-spot (OTS) approximation
  نزدینش ِ درجا   
nazdineš-e darjâ


An approximation in the treatment of photoionized → H II regions, whereby secondary ionizing photons are absorbed immediately very close to their site of emission. The secondary photons, produced by → radiative recombinations directly to the → ground states, are thus ignored with respect to the ionizing photons emitted by the → exciting star. The OTS approximation requires that the ionized gas be sufficiently dense so that secondary ionizing photons are very likely absorbed within the H II region.

on; → spot; → approximation.

Nazdineš, → approximation; dar "in," from Mid.Pers. andar, → intra-.

yek (#)

Fr.: un   

1) The smallest whole number, symbol 1; unity. The → multiplicative identity for real and complex numbers.
2) Being or amounting to a single unit or individual or entire thing, item, or object rather than two or more; a single.

O.E. an, from P.Gmc. *ainaz (cf. O.N. einn, Dan. een, O.Fris. an, Du. een, Ger. ein, Goth. ains), PIE base *oinos, cognate with Pers. yek, as below.

Yek "one, alone," from Mid.Pers. êwak, êv, yak, êk; cf. Baluci hivak "one, single" (Proto-Iranian *aiua-ka-); O.Pers. aiva- "one, alone;" Av. aēuua- "one, alone;" Skt. éka- "one, alone, single;" Gk. oios "alone, lonely;" L. unus "one;" E. one.

one-dimensional flow
  تچان ِ یک-وامونی   
tacân-e yek-vâmuni

Fr.: écoulement uni-dimensionnel   

A hypothetical flow in which all the flow parameters may be expressed as functions of time and one space coordinate only. This single space coordinate is usually the distance measured along the center-line of some conduit in which the fluid is flowing (B. Massey, Mechanics of Fluids, Taylor & Francis, 2006).

one; → dimensional; → flow.

one-to-one correspondence
  هم‌پتوازیِ یک-به-یک   
hampatvâzi-ye yek-be-yek

Fr.: correspondance un à un   

A relationship between two distinct sets of elements such that every member of the first set can be paired with a unique element in the second set; and every member of the second set can be paired with a unique element in the first set. Two sets so related are said to be isomorphic.

one; → correspondence.

piyâz (#)

Fr.: oignon   

A plant, Allium cepa, of the amaryllis family, having an edible, succulent, pungent bulb (

M.E., from Anglo-French union, O.Fr. oignon "onion," from L. unio-, also "pearl," literally "one, unity;" sense connection is the successive layers of an onion.

Mid.Pers. payâz, payâc; cf. Sogd. piyâk "onion," Yidgha piq, Vakhi piûk, Yazghulami piyeq, Kurd. pivaz; maybe related to PIE *peuk- "to prick, to sting, to stab," because of its pungent taste; cf. Gk. peukos "sting, prick, cusp, peak."

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