An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



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Number of Results: 1076
post-Newtonian expansion
  سپانش ِ پسا-نیوتنی   
sopâneš-e pasâ-Newtoni

Fr.: développement post-newtinien   

post-Newtonian formalism.

post-; → Newtonian; → expansion.

post-Newtonian formalism
  دیسه‌گرایی ِ پسا-نیوتنی   
disegerâyi-ye pasâ-Newtoni

Fr.: formalisme post-newtonien   

An approximate version of → general relativity that applies when the → gravitational field is → weak, and the matter → velocity is → small. Post-Newtonian formalism successfully describes the gravitational field of the solar system. It can also be applied to situations involving compact bodies with strong internal gravity, provided that the mutual gravity between bodies is weak. It also provides a foundation to calculate the → gravitational waves emitted by → compact binary star systems, as well as their orbital evolution under radiative losses. The formalism proceeds from the Newtonian description and then, step by step, adds correction terms that take into account the effects of general relativity. The correction terms are ordered in a systematic way (from the largest effects to the smallest ones), and the progression of ever smaller corrections is called the → post-Newtonian expansion.

post-; → Newtonian; → formalism.

  پسا-نووا، پسا-نو-اختر   
pasâ-novâ, pasâ-now-axtar

Fr.: post-nova   

The stage following a nova outburst, when the star has returned to a quiescent state.

post-; → nova.

post-planetary nebula star
  ستاره‌ی ِ پسا-میغ ِ سیاره‌ای   
setâre-ye pasâ-miq-e sayyâre-yi

Fr.: étoile post-nébuleuse planétaire   

An evolved star whose → planetary nebula has dissipated.

post-; → planetary; → nebula; → star.


Fr.: post-modernisme   

Any of a number of trends or styles in architecture, philosophy, literature, and art developed in the latter part of the 20th century often in reaction to → modernism. In philosophy, postmodernists claim that value systems are concoctions of human partial knowledge rather than systems reflecting universal objective truth. The most influential early postmodern philosophers include Jean Baudrillard, Jean-François Lyotard, and Jacques Derrida.

The term postmodernism was first coined by architects to designate an architectural response against the earlier Bauhaus style, which was characterized by box-like apartment buildings, the absence of ornamentation and harmony between the function of a building and its design; → post- + → modernism.

pas afkandan (#)

Fr.: renvoyer, remettre, ajouner   

To put off to a later time; defer.

From L. postponere "put after; neglect; postpone," from → post- "after" + ponere "to put, place," → position.

Pas afkandan, literally "to throw after," "to postpone" (Dehxodâ), from pas- "after," → post-, + afkandan "to throw," → stopword.

  ۱) فراوس؛ ۲) فراوسیدن   
1) farâvas; 2) farâvasidan

Fr.: 1) postulat; 2) postuler   

1a) Math.: An unproved → assumption taken as basic in a mathematical system, and from which (in combination with other → postulates) the propositions of the system are derived, or in terms of which the propositions are proved. In modern usage, postulate is synonymous with → axiom.
1b) Physics: A fundamental principle. For example, the two postulates of special relativity of Einstein are: 1) The laws of physical phenomena are the same when studied in terms of two → reference frames moving at a constant velocity relative to each other. 2) The → velocity of light in free space is the same for all observers and is independent of the relative velocity of the source of light and the observer. See also → Planck postulate.
2a) General: To ask, demand, or claim. To claim or assume the existence or truth of, especially as a basis for reasoning or arguing.
2b) Math.: To assume as a postulate.

From L. postulatum "petition, thing requested," noun use of neuter of p.p. of postulare "to ask, request, demand," akin to poscere "to request."

Farâvas (on the model of piš-nahâd "proposition," and farâ-nemudan "to exhibit, expose"), from farâ-, → pro-, + vas. The second component from Av. vas- "to will, desire, wish, long for," vasəmi "I wish," vasna- "will, favor," ušti- "desire, wish, will," vasô, vasə "at one's will;" cf. O.Pers. vasiy "at will, greatly, utterly," vašna- "will, favor;" Mid.Pers. vasnâd "because, on account of." This word is extant in several Modern Iranian dialects: Tabari vessen "to wish, desire," Gilaki vâssan "to wish, desire," vâsti "desire; for, because, on account of;" Kurd. wistin "to desire, wish," Lâri avessa "to desire;" Nâyini vas "to like;" colloquial Tehrâni vâsé "for;" Lori, Malâyeri biza "pregnancy craving;" cognate with Skt. vaś- "to wish, want, desire," váśa- "wish, desire," vasēna "for, because;" Gk. ekon "voluntary;" PIE base *uek- "to wish."

potâsiom (#)

Fr.: potassium   

A silvery-white metallic chemical element; symbol K (from L. kalium "potash"). Atomic number 19; atomic weight 39.0983; melting point 63.25°C; boiling point 760°C.

Coined by the English chemist Sir Humphrey Davy (1778-1829), who first isolated it in 1807 from electrolysis of caustic potash (KOH); from Mod.L. potassa, Latinized form of E. potash + -ium.


Fr.: potentiel   

1) A latent ability that may or may not be developed; possibility.
2) Physics: The → work required to → move a unit positive → charge, unit magnetic pole, or an amount of → mass respectively from → infinity (i.e. a place infinitely distant from the causes of the field) to a designated point. Gravitational potential is always negative, but the electric or magnetic potentials may be positive or negative.
3) (adj.) Capable of being or becoming, as opposed to → actual.
See also:
chemical potential, → electric scalar potential, → electromagnetic potential, → equipotential surface, → excitation potential, → gravitational potential energy, → ionization potential, → kinetic potential, → magnetic vector potential, → potential barrier, → potential density, → potential difference, → potential energy, → potential energy curve, → potential field, → potential gradient, → potential well, → potentiality, → retarded potential, → scalar potential, → thermodynamic potential, → Yukawa potential.

From L.L. potentialis "potential," from L. potentia "power," potis "powerful, able, capable;" cognate with Av. paiti- "lord, husband;" Mod.Pers. -bad (sepah-bad "general, commander of an army"); Skt. páti- "master, husband;" Gk. posis "husband;" Lith. patis "husband."

Tavand, from tav- + -vand. The first component tav- is the stem of tavân "power, strength," tavânestan "to be powerful, able;" variants tâv, tâb, (dialects) tew "power;" Mid.Pers. tuwan "power, might;" O.Pers. tav- "to have power, to be strong, to be able," tauman- "power, strength," tunuvant- "powerful;" Av. tauu- (tu-) "to be able, strong," tavah- "power," təviši- "strength" (Mod.Pers. tuš "power, ability"); Skt. tavi- "to be strong, to have authority," tavas-, tavisa- "strong, energetic," tavisi- "power, strength;" Gk. taus, saos "healthy;" L. tumere "to be swollen;" PIE *teu- "to swell, be strong." The second component -vand a suffix of adjectives and agent nouns, → actual.
Note: Tavand used as both noun and adjective, such as honarmand (n.) and mard-e honarmand (adj.).

potential barrier
  ورغه‌ی ِ توند   
varqeye tavand

Fr.: barrière de potentiel   

Region in a field of force in which the potential is such that a particle, which is subject to the field, encounters opposition to its passage.

potential; → barrier.

potential density
  چگالی ِ توند   
cagâli-ye tavand

Fr.: densité potentielle   

Of a fluid parcel at pressure P, the density that it would acquire if adiabatically brought to a reference pressure.

potential; → density.

potential difference
  دگرسانی ِ توند   
degarsâni-ye tavand

Fr.: différence de potentiel   

Between two points, the work done in taking the unit test object from one point to the other. Potential is a scalar quantity.

potential; → difference.

potential energy
  کاروژ ِ توند   
kâruž-e tavand

Fr.: énergie potentielle   

Of a system, the work done in changing the system from some standard configuration to its present state. Thus, if a body of mass m is raised vertically through a height h, the work done, mgh, is the increase in potential energy.

potential; → energy.

potential energy curve
  خم ِ کاروژ ِ توند   
xam-e kâruž-e tavand

Fr.: courbe de l'energie potentielle   

A plot that displays the → potential energy of a moving body as a function of its position. It is explained by the → conservation of energy and the conversion of potential energy into → kinetic energy and vice versa.

potential; → energy; → curve.

potential field
  میدان ِ توند   
meydân-e tavand

Fr.: champ de potentiel   

A field that has a → potential. A continuous → vector fieldA in a domain D is a potential field in D if and only if its → work around every closed curve C contained in D is zero: ∫A.ds = 0. Examples include the → gravitational field and the → electrostatic field.

potential; → field.

potential gradient
  زینه‌ی ِ توند   
zine-ye tavand

Fr.: gradient de potentiel   

At a point, the rate of change of potential V, with distance x, measured in the direction in which the variation is a maximum. The intensity F of the field is proportional to the potential gradient, but is oppositely directed: F = -dV/dx.

potential; → gradient.

potential well
  چاه ِ توند   
câh-e tavand

Fr.: puit de potentiel   

Region in a → field of force in which the potential decreases abruptly, and in the surrounding region of which the potential is larger.

potential; → well.


Fr.: potentialité   

1) The state or quality of being potential. Something potential.
2) According to Aristotle, what has the possibility of having → form, in contrast to → actuality; the power to effect change.

potential + → -ity.


Fr.: potentiellement   

With a possibility of becoming actual; possibly.

potential; → -ly.

potentially hazardous asteroid (PHA)
  سیارک ِ توندانه آپه‌ناک   
seyyârak-e tavandâné âpenâk

Fr.: astéroïde potentiellement dangereux   

An asteroid that could make a threatening close approach to the Earth. In technical terms a PHA is defined as having an → absolute magnitude of 22 or brighter and an → Earth Minimum Orbit Intersection Distance (MOID) of less than 0.05 → astronomical unit or 7.5 million km.

potentially; → hazardous; → asteroid.

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