An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



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Number of Results: 1037

Fr.: braconner   

To trespass, especially on another's game preserve, in order to steal animals or to → hunt; to take game or fish illegally (

M.E., from M.Fr. pocher "to thrust, poke," from O.Fr. pochier "poke out, gouge, prod," related to poke (v.), from a Germanic source (compare M.H.G. puchen "to pound, beat, knock," Ger. pochen, Middle Dutch boken "to beat") related to poke (v.).

Beškaridan, from beškar(d), bišgar(d) "hunter, fowler; chase; game; place for hunting," variant of šekâr, → hunt.


Fr.: braconnier   

A person who trespasses on private property, especially to catch fish or game illegally ( See also → hunter.

poach; → -er.


Fr.: braconnage   

The illegal taking of wildlife, in violation of local, state, federal or international law.

poach; → -ing.

Pogson's ratio
  وابر ِ پوگسون   
vâbar-e Pogson

Fr.: rapport de Pogson   

The constant 2.512, which is the 5th → root of 100 (2.5125 = 100); the ratio between two successive stellar → magnitudes.

Pogson's relation; → ratio.

Pogson's relation
  بازانش ِ پوگسون   
bâzâneš-e Pogson

Fr.: relation de Pogson   

The equation that expresses the → magnitude  → difference between two objects in terms of the → logarithm of the → flux  → ratio:
I1/I2 = 2.5(m2 - m1), or
m2 - m1 = 2.5 log(I1/I2),
where m is → apparent magnitude, I flux, and log the logarithm to base 10.

Named after Norman Robert Pogson (1829-1891), the English astronomer, who introduced the magnitude scale in 1856; → relation.

Poincaré recurrence theorem
  فربین ِ باز‌آمد ِ پو‌آنکاره   
farbin-e bâzâmad-e Poincaré

Fr.: théorème de récurrence de Poincaré   

In an → isolated system, any initial state will occur again in the course of the → evolution of the system over a sufficiently long but finite → time.

Poincaré sphere; → recurrence; → theorem.

Poincaré sphere
  کره‌ی ِ پو‌آنکاره   
kore-ye Poincaré

Fr.: sphère de Poincaré   

A representation that permits an easy visualisation of all different states of → polarization of a vector wave. The equator represents → linear polarization; the north pole corresponds to right-circular and the south pole to left- → circular polarization.

Named after Henri Poincaré (1854-1912), French mathematician and theoretical physicist, and a philosopher of science; → sphere.

Poinsot's motion
  جنبش ِ پویءنسو   
jonbeš-e Poinsot

Fr.: mouvement à la Poinsot   

The motion of a torque free rotating rigid body in space, in general whose angular velocity vector precesses regularly about the constant angular momentum factor.

After Louis Poinsot (1777-1859), French physicist and mathematician. He was the inventor of geometrical mechanics, showing how a system of forces acting on a rigid body could be resolved into a single force and a couple.

  ۱) نقطه، پنده؛ ۲) آماجیدن   
1) noqté (#), pandé (#); 2) âmâjidan

Fr.: 1) point; 2) pointer   

1a) General: A sharp or tapering end, as of a dagger; a projecting part of anything.
1b) Physics: Position or time of occurrence, as in boiling point, freezing point, etc.
1c) Math.: A dimensionless geometric element whose location in space is defined solely by its coordinates.
2) To direct a telescope toward a particular position on the sky.

M.E. point(e); O.Fr. point "dot, mark, place, moment;" L. punctum noun use of neuter p.p. of pungere "to prick, pierce."

1) Noqté, loan from Ar. Pandé, variants in classical dictionaries pindé, pendé, fand "a point, dot, mole, freckle;" cf. Skt. prānta- "point, tip, border," from pra "before, forward," → pro-, + ánta- "end, limit, term;" Pali, panta- "remote, solitary;" Prakrit panta " last;" Sindhi pandu "border of a garment;" Lahnda pand, pad "end, top of sugar cane."
2) &ACIRC;mâjidan verb from âmâj "aim, goal," from Proto-Iranian base *āma-, from prefix *ā- + *ma- "to measure;" cf. Av. mati- "point, tip;" O.Pers./Av. mā(y)- "to measure;" Pers. mun/mân "measure," as in Pers. terms pirâmun "perimeter," âzmun "test, trial," peymân "measuring, agreement," peymâné "a measure; a cup, bowl;" cf. Skt. mati "measures," matra- "measure," Gk. metron "measure," L. metrum; PIE base *me- "to measure."

point mass
  نقطه‌جرم، پنده‌جرم، جرم ِ نقطه‌وار، ~ پنده‌وار   
noqté jerm, pandé jerm, jerm-e noqtevâr, ~ pandevâr

Fr.: masse ponctuelle   

A hypothetical object which can be thought of as infinitely small.

point; → mass.

point source
  نقطه‌خن، پنده‌خن، خن ِ نقطه‌وار، ~ پنده‌وار   
noqté xan, pandé xan, xan-e noqtevâr, pande-ye ~

Fr.: source ponctuelle   

A source of radiation at a great distance from the observer; an ideal source of infinitesimal size.

point; → source.

point spread function (PSF)
  کریای ِ گسترش ِ نقطه، ~ ~ پنده   
karyâ-ye gostareš-e noqté, ~ ~ pandé

Fr.: fonction d'étalement du point   

The two-dimensional intensity distribution about the image of a point source.

point; → spread; → function.



The two stars that form the front of the Big Dipper's bowl, away from the handle. More specifically, the stars Dubhe (α Ursae Majoris) and Merak (β Ursae Majoris). A line through β to α passes close to the North Star and they are used for finding it.

point + -er.

Dorahnemâ, literally "the two guides," from do "two" + rah, râh "way, path" (from Mid.Pers. râh, râs "way, street," also rah, ras "chariot;" from Proto-Iranian *rāθa-; cf. Av. raθa- "chariot;" Skt. rátha- "car, chariot," rathyā- "road;" L. rota "wheel," rotare "to revolve, roll;" Lith. ratas "wheel;" O.H.G. rad; Ger. Rad; Du. rad; O.Ir. roth; PIE *roto- "to run, to turn, to roll") + nemâ agent noun of nemudan "to show" (Mid.Pers. nimūdan, nimây- "to show," from O.Pers./Av. ni- "down; into" (Skt. ni "down," nitaram "downward," Gk. neiothen "from below," cf. E. nether, O.E. niþera, neoþera "down, downward, below, beneath," from P.Gmc. *nitheraz, Du. neder, Ger. nieder; PIE *ni- "down, below") + māy- "to measure;" cf. Skt. mati "measures," matra- "measure;" Gk. metron "measure;" L. metrum; PIE base *me- "to measure").


Fr.: pointage   

The act or process of directing a telescope. → point.
The direction in the sky to which the telescope is pointed. Pointing also describes how accurately a telescope can be pointed toward a particular direction in the sky.

Verbal noun of → point.

pointing model
  مدل ِ آماجش   
model-e âmâješ

Fr.: modèle de pointage   

A mathematical model that reproduces the diurnal rotation of the Earth and is used to direct a telescope toward a precise position on the sky.

pointing; → model.


Fr.: poise   

The unit of viscosity in the c.g.s. system, equal to 1 dyne.s/cm2. Symbol: P

Poise, from Jean-Louis-Marie Poiseuille (1797-1869), a French physiologist and physician who studied the flow of liquids through tubes and developed a method for measuring blood pressure.

Poiseuille's law
  قانون ِ پو‌آزوی   
qânun-e Poiseuille

Fr.: loi de Poiseuille   

In fluid dynamics, the law that the rate of flow of a liquid through a horizontal tube of uniform radius is directly proportional to the pressure of the liquid and the fourth power of the radius of the tube and is inversely proportional to the viscosity of the liquid and the length of the tube.

Named after Jean-Louis-Marie Poiseuille (1797-1869), a French physiologist and physician who found the law in 1844; → law.

Poisson distribution
  واباژش ِ پو‌آسون   
vâbâžeš-e Poisson

Fr.: distribution de Poisson   

A → probability function that characterizes → discrete  → random events occurring independently of one another within some definite time or space. It may be regarded as an approximation of the → binomial distribution when the number of events becomes large and the probability of success becomes small. The Poisson distribution is expressed by: f(x) = (λxe)/x!, where λ is the mean number of successes in the interval, e is the base of the → natural logarithm, and x is the number of successes we are interested in.

Named after Siméon Denis Poisson (1781-1840), French mathematician, who developed the application of Fourier series to physical problems and made major contributions to the theory of probability and to the calculus of variations; → distribution.

Poisson's equation
  هموگش ِ پو‌آسون   
hamugeš-e Poisson

Fr.: équation de Poisson   

An equation (∇2φ = 4πGρ) which relates the gravitational (or electromagnetic) potential to the mass density (or charge density).

Poisson distribution; → equation.

  ۱) قطبی؛ ۲) پلار   
1) qotbi; 2) polâr

Fr.: 1) polaire; 2) polar   

1) Of or pertaining to the pole of any sphere, a magnet, an electric cell, etc.
2) A subclass of → cataclysmic variables, the prototype being AM Herculis. Polars are short-period systems in which a → late-type → main sequence star transfers mass to a highly magnetized → white dwarf. The strong magnetic field (10-70 million → gauss) prevents the formation of an → accretion disk, locks both stars in synchronous rotation and guides the accreting matter to accretion spots which are the source of intense X-ray radiation (material impacts on to the white dwarf where it is radiated away).

1) Adj. of → pole.
2) From polar(ization) + (st)ar, because of their → circularly polarized light.

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