An Etymological Dictionary of Astronomy and Astrophysics
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فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

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<< < -es -iv -ti 21 a p abe abs abs aca acc acc acr act ada adh Adr aer AGB air Alf Alg all alp alt AM amo ana And ang ani ano Ant Ant apa apo app app Ara Arc ari Arr ash ass ast ast asy atm ato att aut ave axi Bab bal Bal bar bar bea Bek Bes bia Big bin bin bip biv bla bli blu Boh Bol Bos bou bra bri bro buo cal cal can cap car Car cat cat CCD Cen cen CH cha cha che Che chr cir cir cit cla clo clo clu Coa coe coh col col col com com com com com com com com Com con con con con con con con con con con con con Cop Cor cor cor cos cos cou cou Cow cre cri cro cry cur cya Cyg dan dar dat de- deb dec dec ded def deg del dem den dep des det dev dia dif dif dih dio Dir dis dis dis dis dis dis DO don dou dow dro dur dwa dyn Dys ear ebb ecl edg egg Ein Ela ele ele ele ele ell eme emp enc eng ent epi equ equ equ esc eth Eur Eve exa exc exe exi exp exp ext ext ext fac fal far fed Fer fer fie fin fir fis fla flo flu fol for for fou fra fre Fre fro fut G-t gal gal gam gas Gau Gem gen geo geo geo gia Gli Gol gra gra gra gra gre gri gui H I Hag hal har hat He- hea hel Hel her Hes hie hig his hom hor hot Hub Hug hur hyd hyd hyg hyp ice ide ima Ima imp imp inc inc ind ine inf inf inf ing inn ins ins int int int int int int int int inv Io ion iro isl iso iso Jac jet jud jur Kel Kep kil Klo Kui Lag lam Lap Lar lat law lea len lep Lib lig lim lin lin Lio lit loc LOF lon Lor low lum lun Lup Lyo mac mag mag mag mag mag mai man Mar mas mas mat Max mea mec Meg Mer Mer met met Met mic Mid Mil min Mir mit mod mod mol mon Mor mou mul mul mys nan Nat nau nec neo neu nev New NGC no nom non non nor not nuc nuc num nut obj obs obs occ ocu oft ome Oor ope opp opt opt orb ord ori ort osc out ove oxi pai pan par par par par pas pea pen per per per per Per per pha phi pho pho pho phy pio Pla pla pla pla Pla plu Poi pol pol pol poo pos pos pot pra pre pre pre pre pri pri pro pro pro pro pro Pro pro pse pul pur qua qua qua qua que rac rad rad rad rad rad rad ran rar ray rea rea rec rec red red ref ref reg rel rel rel ren res res res res ret rev Ric rig rin roc roo rot rot Rus Sac sal sat sca sca Sch sci Scu sec sec Sed sel Sel sen ser Sex Sha she sho sid sig sil sim sin siz sla Sma sno sof sol sol sol sol sou sou spa spa spe spe spe sph spi spi spr squ sta sta sta sta ste ste ste Sto Str str str sub sub suc sun sup sup sup sup sur swa syn syn tab tar tek tem ter tes the the the the Tho thr tid tim Tis Too Tor tra tra Tra tra tra tri tri tru Tul tur two Typ ult un- und uni uni unk upp Urc utt val var vec vel ver vib vio vir vis voi vor wan wat wav wax wea Wei whi Wil win WN9 wor X-r yel you zer zod > >>

Number of Results: 13048 Search : far
plus sign
  نشان ِ بیشن   
nešân-e bišan

Fr.: sign plus   

The symbol + indicating summation or a positive quantity. The sign is believed to be a shortened form of the L. word et denoting "and" which was the term for addition. The signs + and - first appeared in an arithmetic book by Johannes Widmann entitled Behennde und hübsche Rechnung, published in Leipzig in 1489.

plus; → sign.

Pluto
  پلوتون   
Pluton (#)

Fr.: Pluton   

A → dwarf planet in the → solar system which until 2006 was known as the 9th major planet. Pluto revolves around the → Sun in a highly elliptical orbit at a mean distance of 39.5 → astronomical units once every about 248 years. The orbit → eccentricity is 0.25 (compare with the Earth's 0.02) yielding a → perihelion distance of 29.66 → astronomical units and an → aphelion distance of 48.87 AU. Its → orbital inclination is 17 degrees, which is much higher than those of the other planets. Pluto's mass is 1.308 × 1022 kg, that is 0.00218 Earth mass (0.177 Moon mass), its equatorial radius ib 0.19 Earth radius, and its → rotation period is equal to 6.39 Earth days. It has five known → satellites, in order of distance from Pluto: → Charon, → Styx, → Nix, → Kerberos, and → Hydra. Pluto's radius is estimated to be about 1150 km (0.18 Earths). Pluto is smaller than seven of the solar system's satellites (the → Moon, → Io (Jupiter I) , → Europa, → Ganymede, → Callisto, → Titan, and → Triton). Pluto's surface has an estimated temperature of 37.5 K and is composed of more than 98% → nitrogen  → ice, with traces of → methane and → carbon monoxide.

In Roman mythology, Pluto is the god of the underworld and Judge of the dead, from L. Pluto, Pluton, from Gk. Plouton "god of wealth," literally "wealth, riches." Pluto was the son of Saturn. The alternative Gk. name is Hades.

plutonium
  پلوتونیوم   
plutoniom (#)

Fr.: plutonium   

A → radioactive → chemical element, symbol Pu. → Atomic number 94; → mass number of most stable isotope 244; → melting point 640 °C; → boiling point 3,235 °C. It was first synthesized in 1940 by American chemists Glenn T. Seaborg, Edwin M. McMillan, Joseph W. Kennedy and Arthur C. Wahl in the → nuclear reaction: 92U238 + 0n193Np239 + β- (23.5 minutes) → 94Pu239 + β- (2.36 days). The → half-life of 94Pu239 is 2.44 × 104 yr. Plutonium-239 is a → fissile isotope.

The name derives from the planet → Pluto. It was selected because it is the next planet in the solar system beyond the planet → Neptune and the element plutonium is the next element in the → periodic table beyond → neptunium.

poach
  بشکریدن   
beškaridan

Fr.: braconner   

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

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.

poacher
  بشکرنده   
beškarandé

Fr.: braconnier   

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

poach; → -er.

poaching
  بشکر   
beškar

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.

point
  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) Âmâjidan, 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.

Pointers
  دورهنما   
dorahnemâ

Fr.:   

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").

pointing
  آماجش   
âmâješ

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.

poise
  پو‌آز   
poise

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.

<< < -es -iv -ti 21 a p abe abs abs aca acc acc acr act ada adh Adr aer AGB air Alf Alg all alp alt AM amo ana And ang ani ano Ant Ant apa apo app app Ara Arc ari Arr ash ass ast ast asy atm ato att aut ave axi Bab bal Bal bar bar bea Bek Bes bia Big bin bin bip biv bla bli blu Boh Bol Bos bou bra bri bro buo cal cal can cap car Car cat cat CCD Cen cen CH cha cha che Che chr cir cir cit cla clo clo clu Coa coe coh col col col com com com com com com com com Com con con con con con con con con con con con con Cop Cor cor cor cos cos cou cou Cow cre cri cro cry cur cya Cyg dan dar dat de- deb dec dec ded def deg del dem den dep des det dev dia dif dif dih dio Dir dis dis dis dis dis dis DO don dou dow dro dur dwa dyn Dys ear ebb ecl edg egg Ein Ela ele ele ele ele ell eme emp enc eng ent epi equ equ equ esc eth Eur Eve exa exc exe exi exp exp ext ext ext fac fal far fed Fer fer fie fin fir fis fla flo flu fol for for fou fra fre Fre fro fut G-t gal gal gam gas Gau Gem gen geo geo geo gia Gli Gol gra gra gra gra gre gri gui H I Hag hal har hat He- hea hel Hel her Hes hie hig his hom hor hot Hub Hug hur hyd hyd hyg hyp ice ide ima Ima imp imp inc inc ind ine inf inf inf ing inn ins ins int int int int int int int int inv Io ion iro isl iso iso Jac jet jud jur Kel Kep kil Klo Kui Lag lam Lap Lar lat law lea len lep Lib lig lim lin lin Lio lit loc LOF lon Lor low lum lun Lup Lyo mac mag mag mag mag mag mai man Mar mas mas mat Max mea mec Meg Mer Mer met met Met mic Mid Mil min Mir mit mod mod mol mon Mor mou mul mul mys nan Nat nau nec neo neu nev New NGC no nom non non nor not nuc nuc num nut obj obs obs occ ocu oft ome Oor ope opp opt opt orb ord ori ort osc out ove oxi pai pan par par par par pas pea pen per per per per Per per pha phi pho pho pho phy pio Pla pla pla pla Pla plu Poi pol pol pol poo pos pos pot pra pre pre pre pre pri pri pro pro pro pro pro Pro pro pse pul pur qua qua qua qua que rac rad rad rad rad rad rad ran rar ray rea rea rec rec red red ref ref reg rel rel rel ren res res res res ret rev Ric rig rin roc roo rot rot Rus Sac sal sat sca sca Sch sci Scu sec sec Sed sel Sel sen ser Sex Sha she sho sid sig sil sim sin siz sla Sma sno sof sol sol sol sol sou sou spa spa spe spe spe sph spi spi spr squ sta sta sta sta ste ste ste Sto Str str str sub sub suc sun sup sup sup sup sur swa syn syn tab tar tek tem ter tes the the the the Tho thr tid tim Tis Too Tor tra tra Tra tra tra tri tri tru Tul tur two Typ ult un- und uni uni unk upp Urc utt val var vec vel ver vib vio vir vis voi vor wan wat wav wax wea Wei whi Wil win WN9 wor X-r yel you zer zod > >>